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PLoS One plos plosone PLOS One 1932-6203 Public Library of Science San Francisco, CA USA 10.1371/journal.pone.0323919 PONE-D-24-29546 Research Article Biology and life sciencesMicrobiologyMedical microbiologyMicrobial pathogensViral pathogensImmunodeficiency virusesHIV Medicine and health sciencesPathology and laboratory medicinePathogensMicrobial pathogensViral pathogensImmunodeficiency virusesHIV Biology and life sciencesOrganismsVirusesViral pathogensImmunodeficiency virusesHIV Biology and life sciencesOrganismsVirusesImmunodeficiency virusesHIV Biology and life sciencesOrganismsVirusesRNA virusesRetrovirusesLentivirusHIV Biology and life sciencesMicrobiologyMedical microbiologyMicrobial pathogensViral pathogensRetrovirusesLentivirusHIV Medicine and health sciencesPathology and laboratory medicinePathogensMicrobial pathogensViral pathogensRetrovirusesLentivirusHIV Biology and life sciencesOrganismsVirusesViral pathogensRetrovirusesLentivirusHIV Medicine and health sciencesDiagnostic medicineVirus testing Medicine and health sciencesEpidemiologyHIV epidemiology People and placesGeographical locationsAfricaZambia Medicine and health sciencesUrologyGenitourinary infectionsSyphilis Medicine and health sciencesMedical conditionsInfectious diseasesSexually transmitted diseasesSyphilis Medicine and health sciencesMedical conditionsInfectious diseasesBacterial diseasesTreponematosesSyphilis Medicine and health sciencesMedical conditionsTropical diseasesNeglected tropical diseasesTreponematosesSyphilis Medicine and health sciencesPublic and occupational healthPreventive medicineHIV prevention Medicine and health sciencesPharmaceuticsDrug therapy Medicine and health sciencesEpidemiologyMedical risk factors Local data for local programming: Results from an HIV biobehavioral survey among people who inject drugs in Livingstone, Lusaka, and Ndola, Zambia, 2021 HIV biobehavioral survey results among PWID in three Zambian towns, 2021 https://orcid.org/0000-0002-7808-2208 Woytowich Daniel Formal analysis Methodology Validation Visualization Writing – original draft Writing – review & editing 1 * McIntyre Anne F. Conceptualization Formal analysis Investigation Methodology Supervision Validation Writing – original draft Writing – review & editing 1 Solomon Hiwote Conceptualization Formal analysis Supervision Validation Writing – original draft Writing – review & editing 1 ¤ Hanunka Brave Conceptualization Data curation Methodology Writing – original draft Writing – review & editing 2 Chelu Lazarus Conceptualization Data curation Methodology Writing – review & editing 3 Nkumbula Tepa Data curation Formal analysis Writing – review & editing 3 Tally Leigh Writing – review & editing 2 Handema Ray Conceptualization Data curation Methodology Writing – review & editing 4 Khondowe Shepherd Conceptualization Data curation Methodology Writing – review & editing 4 Kapungu Kelvin Conceptualization Data curation Methodology Writing – review & editing 4 Chilukutu Lophina Writing – review & editing 3 Bwalya Innocent Conceptualization Data curation Methodology Writing – review & editing 4 Mulemfwe Chipili Conceptualization Data curation Methodology Writing – review & editing 3 Mwansa Melvin Writing – review & editing 3 Mutale Kennedy Methodology Validation Writing – review & editing 5 https://orcid.org/0000-0001-5816-8197 Philip Neena M. Project administration Validation Writing – review & editing 6 https://orcid.org/0000-0002-1699-4324 Reid Giles Data curation Formal analysis Methodology 6 Neal Joyce J. Conceptualization Methodology Writing – review & editing 7 https://orcid.org/0000-0002-9748-9273 Lahuerta Maria Conceptualization Data curation Funding acquisition Methodology Project administration Supervision Writing – review & editing 6 https://orcid.org/0000-0001-5119-5811 Parmley Lauren E. Conceptualization Data curation Funding acquisition Methodology Supervision Writing – review & editing 6 Chung Hannah Methodology Writing – review & editing 6 Hakim Avi J. Methodology Writing – review & editing 1 ¤ Hines Jonas Z. Writing – review & editing 2 Kim Evelyn Writing – review & editing 1 ¤ Mwale John Conceptualization Methodology Writing – review & editing 8 Mulenga Lloyd B. Conceptualization Project administration Supervision Writing – review & editing 8 9 Division of Global HIV and TB, U.S. Centers for Disease Control and Prevention, Global Health Center, Atlanta, Georgia, United States of America Division of Global HIV and TB, U.S. Centers for Disease Control and Prevention, Global Health Center, Lusaka, Zambia ICAP at Columbia University, Mailman School of Public Health, Lusaka, Zambia Tropical Disease Research Centre, Ndola, Zambia Key Populations Consortium, Lusaka, Zambia ICAP at Columbia University, Mailman School of Public Health, New York, New York, United States of America Division of Global HIV and TB, U.S. Centers for Disease Control and Prevention, Global Health Center, Phnom Penh, Cambodia Ministry of Health Zambia, National HIV/AIDS/STI/TB Council, Lusaka, Zambia Division of Infectious Diseases, University of Zambia, School of Medicine, Lusaka, Zambia Jahun Ibrahim Editor SKYDA Health Nigeria, NIGERIA

The authors have declared that no competing interests exist.

Current Address: U.S. Centers for Disease Control and Prevention, Global Health Center, Division of Global HIV and TB, Atlanta, Georgia, United States of America

 * E-mail: toj2@cdc.gov 2752025 2025 20 5 e0323919 2882024 1742025 This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication. Introduction

People who inject drugs (PWID) in Zambia are an understudied population at high risk for HIV acquisition and transmission. We report here on the progress within the PWID communities of Livingstone, Lusaka, and Ndola, Zambia towards the Joint United Nations Programme on HIV/AIDS (UNAIDS) 95-95-95 targets.

 Methods

A biobehavioral survey used respondent-driven sampling to survey 235 PWID in Livingstone, 349 in Lusaka, and 259 in Ndola in 2021–22. Questions on HIV and injection drug use were administered, and blood was collected for HIV, syphilis, Hepatitis B, and Hepatitis C testing. Weighted prevalence and 95% confidence intervals (CIs) were calculated using Gile’s sequential sampling estimator.

 Results

In Livingstone, Lusaka, and Ndola, HIV prevalence among PWID was 11.9% (95% CI: 7.3, 16.5), 7.3% (95% CI: 4.5, 10.2), and 21.9% (95% CI: 14.5, 29.3), respectively. Among HIV-positive PWID in Livingstone, 70.7% (95% CI: 55.4, 85.0) were aware of their HIV status (95% is 1st UNAIDS target), 100% of those were on antiretroviral therapy (ART) (95% is 2nd UNAIDS target), and 100% of those achieved viral load suppression (VLS) (95% is 3rd UNAIDS target). In Lusaka, 66.0% (95% CI: 49.3, 82.2) were aware, 75.7% (95% CI: 51.1, 99.9) were on ART, and 66.3% (95% CI: 42.1, 90.9) achieved VLS. In Ndola, 60.2% (95% CI: 44.1, 76.0), 100%, and 90.2% (95% CI: 82.2, 98.3) were aware, on ART, and achieved VLS, respectively.

 Conclusions

Awareness of HIV status was low among PWID living in Livingstone, Lusaka, and Ndola, Zambia. Treatment and VLS progress were lacking in Lusaka and Ndola as well with Lusaka showing the least progress toward all three UNAIDS targets. Our site-level findings highlight critical gaps in PWID-specific HIV awareness, treatment, and VLS status in three major urban areas in Zambia that limit progress toward HIV epidemic control in this hard-to-reach population.

 http://dx.doi.org/10.13039/100009054 U.S. President’s Emergency Plan for AIDS Relief 1NU2GGH002056 https://orcid.org/0000-0001-5816-8197 PhilipNeena M. This activity was funded by the US President’s Emergency Plan for AIDS Relief (PEPFAR) (https://www.state.gov/pepfar/) through the US Centers for Disease Control and Prevention (CDC) under the terms of cooperative agreement “Supporting sustainable surveillance systems among key populations and support the Government of Zambia to improve HIV-related services for KPs” (Prime Award No. 1NU2GGH002056). The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the funding agencies. CDC employees, whose specific roles are outlined in the author contributions section, provided technical assistance and input into the study design, data collection, data analysis, decision to publish, and preparation of the manuscript.”\ Data Availability The underlying data for this study are owned by the Zambian Ministry of Health and the National AIDS Council. Due to the sensitive nature of the data, which involve key populations that face legal and social risks, there are strict ethical and legal restrictions on data sharing. These restrictions are mandated by the institutional review board (IRB) requirements to protect participant privacy and confidentiality. For these reasons, the de-identified data can only be accessed upon request and after approval by the relevant Zambian health authorities. Researchers interested in accessing the data should contact Dr. Kebby Chongwe Musokotwane, the Director General of the National HIV/AIDS/STI/TB Council [KMusokotwane@nacsec.org.zm; +260-211-255044]. Requests will be evaluated to ensure compliance with ethical standards and participant safety." Introduction

People who inject drugs (PWID) are especially susceptible to acquiring HIV and accounted for approximately 8.0% of new HIV infections globally in 2022 [1–6]. A major reason for this is the sharing of used needles [1,7–9]. Other factors include social isolation, poor access to health care, stigma, discrimination, and criminalization [2,7,10–14]. Whereas the world’s general population of 15–49-year-olds have an HIV prevalence of 0.6% (95% CI: 0.6, 0.7) [15], 15–64-year-old PWID worldwide have an HIV prevalence of 15.2% (95% CI: 10.3, 20.9) [11]. In Sub-Saharan Africa (SSA) the HIV prevalence among the general population of 15–49-year-olds is 3.4% (95% CI: 3.1, 3.8) [15], compared to 11.2% (95% CI: 5.4, 19.0) among 15–64-year-old PWID [11]. HIV transmission occurs between PWID when injecting equipment is shared and from PWID to others through activities like sex work [16], in which 19.6% (95% CI: 11.1, 31.3) of SSA PWID have recently (within a year) participated [11].

The Joint United Nations Programme on HIV/AIDS (UNAIDS) 95-95-95 targets [17] are intended to be achieved by 2030 [17,18]. The first target is for 95% of people living with HIV (PLHIV) to be aware of their HIV status. The second is for 95% of PLHIV who are aware of their serostatus to receive sustained antiretroviral therapy (ART), and the third is for 95% of those on ART to achieve viral load (VL) suppression (VLS) [17,18], defined as HIV RNA of <1000 copies/mL during the most recent VL test [17–19]. UNAIDS 95-95-95 goals involve reaching these benchmarks not only in the general population, but in priority subpopulations [17] like PWID as well.

In 2021, estimates for the 1st, 2nd, and 3rd 95-95-95 target proportions in Zambia’s general population were 88.7%, 98.0%, and 96.3%, respectively, indicating that the 2nd and 3rd goals have already been met [20]. However, progress toward the 1st target lags behind by over six percentage points [20]. Although there is some limited information about injection drug use and HIV in SSA [21–25], specific data on the status of the HIV epidemic within Zambia’s PWID community are lacking [13]. Of note, the injection of narcotic and psychotropic substances, along with their precursor chemicals is illegal in Zambia. In addition, there are no PEPFAR or government-sponsored Opioid Agonist Maintenance Therapy (OAMT) or Needle and Syringe Programs (NSPs) available for the treatment of stimulant dependence in Zambia. There is no published information on HIV awareness, ART uptake, and/or VLS among Zambian PWID communities. Elucidating current progress toward 95-95-95 targets among PWID in Zambia is essential for understanding the performance of current outreach and interventions to this group [26–28], and how those might be improved for greater impact.

In 2021, Zambia implemented the first ever probability-based biobehavioral survey (BBS) to estimate HIV prevalence, HIV-related indicators, syphilis, Hepatitis B, and Hepatitis C prevalence among PWID. Here, we report site-specific progress toward reaching the UNAIDS 95-95-95 targets among PWID in Livingstone, Lusaka, and Ndola, Zambia. Sociodemographic variables, injecting practices, sexual behaviors, stigma, discrimination, risk perception, and service use that may have influenced the 95-95-95 results were examined as well. Our goal was to analyze and interpret information at the local level, rather than at the national or provincial level, to ensure that any nuanced differences across survey sites would not be masked in our results and therefore possibly overlooked in future program design.

 Methods Study design and eligibility criteria

Three survey sites (Livingstone, Lusaka, and Ndola) were selected based on a previous formative assessment of persons who use drugs in Zambia [13]. In the six months prior to the survey, the consensus estimate among 15–64-year-olds for the PWID population size in Livingstone, Lusaka, and Ndola was 0.9% (95% CI: 0.7, 1.5), 0.2% (95% CI: 0.1, 0.5), and 0.6% (95% CI: 0.4, 0.7), respectively. Livingstone is in Southwest Zambia on the border with Zimbabwe and has a high influx of visitors for Victoria Falls, but nonetheless has the smallest population of the three survey sites. Lusaka is in Central Zambia, is the nation’s capital, and has the largest population of the three sites. Ndola lies roughly 300 km to the north of Lusaka near the border with the Democratic Republic of the Congo. PWID in Livingstone, Lusaka, and Ndola were recruited using respondent-driven sampling (RDS), a chain referral method used for accessing hard-to-sample populations and approximating a probability sample in the absence of a sampling frame [29,30]. In 2016–17, the proportion of 15–59-year-old PLHIV with VLS in Zambia was 59.2% [20]. Assuming a design effect of 2 and nonresponse rate of 5%, a sample size of 195 HIV-positive participants was needed for a two-sided 95% confidence interval (CI) ranging from 50.0% to 70.0% when the proportion of HIV-positive people with VLS was 60.0%. Therefore, a target sample size of 780 PWID for each city was calculated to obtain a sample size of 195 HIV-positive PWID participants per city assuming an HIV prevalence of 25%. However, this was determined to be unattainable after consultation with local stakeholders supporting PWID in Zambia due to workforce and funding limitations. Therefore, this target was divided across the sites based upon the size of the PWID population in each city (Livingstone, n = 215; Lusaka, n = 350; Ndola, n = 215).

PWID were eligible if they were 16 years or older; provided verbal informed consent; spoke English, Chinyanja, Cibemba, Silozi, Kikaonde, or Chitonga; lived in the survey city; self-reported injecting drugs for non-medical purposes in the past three months; had a valid survey coupon; and did not previously participate in the survey. Six to eight PWID seeds began recruitment of peers. Seeds were purposively selected based on eligibility for the survey, large social networks, enthusiasm and support for the survey, and a diverse range of sociodemographic characteristics. Successive recruitment waves were carried out until the desired sample size was reached. Recruitment occurred from November 2021 to February 2022.

 Survey process and data collection

During the first of two survey visits, candidate participants presented recruitment coupons and were screened for eligibility. Verbal informed consent was obtained for the questionnaire, biomarker testing, and storage of blood samples. Staff administered tablet-based in-person interviews using standardized instruments. Interview domains included: demographics, sexual history, injection drug use history, HIV knowledge, uptake of HIV and sexually transmitted infection (STI) services, history of STIs, social cohesion, stigma, and COVID-19. The two-item Patient Health Questionnaire (PHQ-2) was used to screen for depression and the Alcohol Use Disorders Identification Test (AUDIT) for alcohol disorders [31,32]. Participants were tested for HIV, HIV VL, active syphilis, hepatitis B virus (HBV), and hepatitis C virus (HCV) as described below, received pre-and post-test counseling along with their rapid test results, and scheduled a second visit. Referrals to care were provided to those who tested positive for HIV, active syphilis, HBV, and HCV. Participants who had STI symptoms were also referred to care. Approximately two weeks later, participants returned for the second visit to provide information about the number and characteristics of peers they recruited. Persons who tested positive for HIV received HIV VL test results. Participants received $13.00 and $5.00 reimbursement for their first and second visits, respectively; along with $3.00 for each peer they referred that completed a survey. Coupon distribution was monitored using an RDS coupon management spreadsheet and ceased when 95% of the sample size was reached, whereas overall recruitment monitoring occurred weekly until both sample size and convergence were reached.

 Laboratory and testing procedures

Participants who consented to being tested received pre-test counseling for HIV, active syphilis, HBV, and HCV that followed national guidelines [33]. Venipuncture was used to collect 15 mL of venous blood into two 7.5 mL EDTA tubes for HIV, HIV VL, active syphilis, HBV, and HCV testing. Rapid testing for HIV, syphilis, HBV, and HCV was performed at the survey site using venous whole blood from the first 7.5 mL tube. Participants with a reactive result on both screening (Determine™ HIV-1/2 [Abbott Molecular Inc., Des Plaines, Illinois, United States]) [34] and confirmatory HIV tests (SD Bioline™ HIV-1/2 [Abbott Molecular Inc., Des Plaines, Illinois, United States]) [35] were classified as HIV-positive. Samples reactive on the initial test but nonreactive on the confirmatory test were retested, and results were returned immediately. The remaining blood and second 7.5 mL tube were then centrifuged at 3000 revolutions per minute to separate into plasma which was stored at -20°C until it was shipped to the Tropical Diseases Research Centre (TDRC) laboratory in Ndola by a trained driver at room temperature, which occurred weekly. Plasma was stored at −20°C in the TDRC laboratory until it was tested, within one week of arrival, then kept at −80°C for long-term storage. Laboratory-based testing was conducted at TDRC for active syphilis, HIV VL, and HIV recency classification per the recent infection testing algorithm. Confirmation of positive rapid assays were conducted for HIV, HCV, and syphilis. Participants with discordant results in the confirmatory test were tested again during their second visit. For those classified as HIV-positive, HIV-1 VL testing was performed using the COBAS AmpliPrep/COBAS TaqMan™ HIV-1 Test, v2.0 (Roche Molecular Diagnostics, Indianapolis, Indiana, United States) [36]. Active syphilis testing was conducted using the Chembio™ DPP Syphilis Screen and Confirm Assay (Medford, New York, United States) [37], with confirmatory testing being done with the SD Bioline™ Syphilis 3.0 kit (Abbott Molecular Inc., Chicago, Illinois, United States) [38]. Acute and chronic HBV was tested for with the Determine™ HBsAg test (Abbott Molecular Inc., Chicago, Illinois, United States) [39]. Testing for current or past HCV infection was conducted with the SD Bioline™ HCV test (Abbott Molecular Inc., Chicago, Illinois, United States) [40] whereas confirmatory testing was conducted with the Applied Biosystems™ 7500 RT PCR platform (Waltham, Massachusetts, United States) [41] and the Applied Biosystems Taqman™ Fast Virus 1-Step Master Mix for qPCR (Waltham, Massachusetts, United States) [42].

 Data management and analysis

RDS Analyst software (Los Angeles, California, United States) [43], SAS software (Cary, North Carolina, United States) [44], and R software [45], was used for data management, weighting, and analysis. Weighted prevalence and 95% CIs for all variables were calculated using Gile’s sequential sampling estimator [46]. Participants were categorized as being aware of their HIV status (1st 95 target) if they reported a prior HIV diagnosis and/or had a VL of <200 copies/mL. Of those, PWID were classified as on ART (2nd 95) based on self-report of current ART use and adjusted for a VL of <200 copies/mL [47]. VLS (3rd 95) was defined as having a VL of <1000 copies/mL.

 Human subjects considerations

This survey was conducted by the Zambian National HIV/AIDS/STI/TB Council (NAC), the Zambian Ministry of Health (MoH), ICAP at Columbia University, and the Tropical Diseases Research Centre (TDRC). It was funded by the United States (US) President’s Emergency Plan for AIDS Relief (PEPFAR) and supported by the US Centers for Disease Control and Prevention (CDC). The survey protocol was reviewed and approved by the Columbia University Medical Center Institutional Review Board, TDRC ethics committee, Zambia MoH, and National Health Research Authority. This activity was also reviewed by CDC, deemed not research, and was conducted consistent with applicable US federal law and CDC policy (45 C.F.R. 46). The NAC was interested in including 16–17-year-olds in this study due to high incidence of HIV in this population and lack of data on them. Since the legal age of consent is 16 years in Zambia, people of this age group were included after providing consent. Verbal informed consent on procedures, potential risks, benefits, and how to report concerns was obtained from all participants and was witnessed by staff trained in human subject protections. Verbal, as opposed to written consent, was obtained since this survey met both conditions of 45CFR46.117(c) in that (1) the signed consent would be the only record that could link respondents to the survey which would increase the risk of breach of confidentiality, and (2) the survey presents no more than minimal risk of harm to respondents and involves no procedures for which written consent is normally required outside of the research context. After verbal consent was given, it was documented by the interviewer signing on behalf of the participant. All participation was confidential. CDC investigators had no interaction with participants and no access to identifiable data or specimens.

 Results Recruitment, screening, enrollment, and testing

Six seeds were used in Livingstone and Ndola, whereas eight were used in Lusaka (Table 1). Mean number of recruits per seed ranged from 38.2–57.0. The longest wave was 18 (Lusaka). Coupon return rate ranged from 48.2%-53.8%; and 249, 479, and 303 PWID were screened in Livingstone, Lusaka, and Ndola, respectively. Of those, 235, 349, and 259 were eligible, enrolled, and tested for biomarkers. Of those, 176, 253, and 184 participants returned for a second visit.

10.1371/journal.pone.0323919.t001 Recruitment, screening, enrollment, and testing characteristics—Livingstone, Lusaka, and Ndola, Zambia, 2021.
Livingstone Lusaka Ndola
Number of seeds 6 8 6
Mean number of recruits by seed 38.2 57.0 42.2
Length of longest wave 6 18 8
Percent of coupons returned 48.2% 51.5% 53.8%
Number of PWID screened 249 479 303
Number (%) of PWID eligible out of those screened 235 (94.4) 349 (72.9) 259 (85.5)
Number (%) of PWID enrolled out of those eligible 235 (100.0) 349 (100.0) 259 (100.0)
Number (%) tested for biomarkers out of those enrolled 235 (100.0) 349 (100.0) 259 (100.0)
Number (%) returned for second visit out of those enrolled 176 (74.9) 253 (72.5) 184 (71.0)
Sociodemographic and sexual history characteristics Livingstone.

The median age of PWID in Livingstone was 23.0 years (interquartile range [IQR]: 20.0–30.0) (Table 2). The majority were male (83.6%, 95% CI: 73.4, 93.6), never married (76.3%, 95% CI: 70.3, 82.3), had no children (59.2%, 95% CI: 50.9, 67.6), completed at least a secondary education (58.4%, 95% CI: 50.7, 66.1), and 2.5% (95% CI: 0.6, 4.4) were homeless. Median age at first sex was 15.0 years (IQR: 13.0–17.0), 60.2% (95% CI: 52.8, 67.6) had six or more lifetime vaginal and/or anal sexual partners, 15.8% (95% CI: 9.2, 22.4) had been forced to have sex in their lifetime, and 6.8% (95% CI: 2.1, 11.5) sold sex, or were a sexually exploited minor, to at least three people in the six months preceding the survey.

10.1371/journal.pone.0323919.t002 Sociodemographic and sexual history characteristics of PWID—Livingstone, Lusaka, and Ndola, Zambia, 2021.
Livingstone Lusaka Ndola
Sample Size n = 235 n = 349 n = 259
Sample Population Sample Population Sample Population
n % % (95% CI) n % % (95% CI) n % % (95% CI)
Median Age (IQR), years 23.0 (20.0, 30.0) 24.0 (21.0, 28.0) 28.0 (23.0, 32.0)
Age Categories, years
 16-24 135 57.4 57.7 (48.6-66.9) 172 49.3 51.2 (43.8-58.5) 80 30.9 30.4 (21.5-39.1)
 25-34 72 30.6 30.9 (23.0-38.8) 149 42.7 41.6 (34.6-48.6) 124 47.9 50.8 (42.3-59.3)
 35 and over 28 11.9 11.3 (7.0-15.7) 28 8.0 7.3 (3.6-11.0) 55 21.2 18.9 (11.6-26.2)
Sex
 Male 199 84.7 83.6 (73.4-93.6) 335 96.0 97.4 (96.0-98.9) 173 66.8 65.9 (56.0-75.9)
 Female 36 15.3 16.4 (6.3-26.6) 13 3.7 2.4 (1.0-3.8) 77 29.7 29.8 (20.6-39.1)
Marital Status
 Never Married 178 75.7 76.3 (70.3-82.3) 240 68.8 70.3 (63.5-77.4) 151 58.3 58.0 (49.0-66.8)
 Married 20 8.5 7.3 (4.1-10.6) 33 9.5 7.8 (4.1-11.6) 46 17.8 17.6 (10.9-24.3)
 No longer Married 37 15.7 16.4 (11.3-21.5) 76 21.8 21.8 (16.0-28.0) 62 23.9 24.4 (16.8-32.1)
Number of living children
 None 132 56.2 59.2 (50.9-67.6) 164 47.0 54.4 (46.7-62.1) 96 37.1 37.6 (28.6-46.6)
 1 60 25.5 23.1 (17.1-29.0) 128 36.7 31.0 (24.2-36.8) 83 32.0 30.7 (22.4-38.9)
 2 or more 43 18.3 17.7 (11.6-23.9) 57 16.3 15.1 (9.9-20.3) 80 30.9 31.8 (23.4-40.2)
Highest level of education completed
 None 13 5.5 6.7 (1.3-12.1) 25 7.2 7.3 (3.4-11.3) 0 0 –
 Primary 91 38.7 34.8 (27.5-42.2) 103 29.5 32.7 (26.4-39.1) 34 13.1 11.9 (6.3-17.5)
 Secondary or higher 131 55.7 58.4 (50.7-66.1) 221 63.3 60.0 (53.1-66.8) 224 86.5 87.7 (82.1-93.4)
Homeless 8 3.4 2.5 (0.6-4.4) 40 11.5 13.2 (7.8-18.6) * * *
Median age at first sex (IQR), years 15.0 (13.0, 17.0) 16.0 (15.0, 18.0) 17.0 (16.0, 19.0)
Age at first sex, years
 <15 102 43.4 42.0 (34.1-49.8) 76 21.8 18.4 (13.6-23.2) 53 20.5 22.2 (15.2-29.3)
 15-19 115 48.9 50.1 (42.4-58.0) 235 67.3 67.7 (61.5-73.9) 155 59.8 56.8 (48.9-64.7)
 ≥ 20 18 7.7 7.9 (3.8-11.9) 38 10.9 13.0 (7.4-20.2) 51 19.7 21.0 (10.5-27.7)
Lifetime number of sexual partners (vaginal and/or anal sex)
 1 9 3.8 2.9 (0.7-5.1) 19 5.4 6.1 (3.1-9.0) * * *
 2 19 8.1 8.0 (3.9-12.1) 27 7.7 9.2 (4.6-14.0) 13 5.0 8.1 (3.2-12.9)
 3-5 64 27.2 25.1 (18.4-31.7) 120 34.4 35.6 (29.1-42.3) 68 26.3 24.3 (17.4-31.2)
 6 or more 133 56.6 60.2 (52.8-67.6) 172 49.3 46.0 (39.1-52.6) 172 66.4 66.5 (58.4-74.6)
Ever forced to have sex 37 15.7 15.8 (9.2-22.4) 32 9.2 9.1 (5.4-12.7) 96 37.1 35.9 (28.2-43.7)
Number of people whom you sold vaginal and/or anal sex to in the last 6 monthsꝉ
 None 211 89.8 89.9 (84.6-95.2) 338 96.8 97.6 (95.9-99.3) 175 67.6 70.6 (62.5-78.7)
 1-2 7 3.0 3.3 (0.3-6.2) 9 2.6 2.1 (0.4-3.8) 31 12.0 10.0 (5.3-14.6)
 3 or more 17 7.2 6.8 (2.1-11.5) * * * 43 16.6 14.9 (8.8-21.1)

Population estimates and 95% Confidence Intervals are weighted using Gile’s SS estimator, whereas sample estimates are unweighted. CI: Confidence Interval. IQR: Interquartile Range. *Suppressed due to number being ≤ 5. ꝉIf one sold sex prior to the age of 18, they were a sexually exploited minor.

 Lusaka.

Median age of PWID in Lusaka was 24.0 years (IQR: 21.0–28.0) and 97.4% were male (95% CI: 96.0, 98.9). The majority were never married (70.3%, 95% CI: 63.5, 77.4), had no children (54.4%, 95% CI: 46.7, 62.1), 60.0% completed at least a secondary education (95% CI: 53.1, 66.8), and 13.2% (95% CI: 7.8, 18.6) were homeless. Median age at first sex was 16.0 years (IQR: 15.0–18.0), 46.0% (95% CI: 39.1, 52.6) had six or more lifetime sexual partners, 9.1% (95% CI: 5.4, 12.7) had been forced to have sex, and 2.1% (95% CI: 0.4, 3.8) sold sex, or were a sexually exploited minor, to 1–2 people in the last six months.

 Ndola.

Median age of PWID in Ndola was 28.0 years (IQR: 23.0–32.0) and almost a third (29.8%, 95% CI: 20.6, 39.1) were female. Most were never married (58.0%, 95% CI: 49.0, 66.8), 31.8% had two or more children (95% CI: 23.4, 40.2), and 87.7% completed secondary education or higher (95% CI: 82.1, 93.4). Median age at first sex was 17.0 years (IQR: 16.0–19.0), 66.5% (95% CI: 58.4, 74.6) had six or more lifetime sex partners, 35.9% had been forced to have sex (95% CI: 28.2, 43.7), and 14.9% (95% CI: 8.8, 21.1) sold sex, or were a sexually exploited minor, to three or more people in last six months.

 Injection drug use and history of stigma, discrimination, and criminalization Livingstone.

Median age when PWID in Livingstone started injecting was 19.0 years (IQR: 17.0–22.0) and they had injected for a median duration of 4.0 years (IQR: 2.0–6.0) (Table 3). Almost half (46.5%, 95% CI: 38.5–54.5) had injected drugs within a day of the survey, 30.1% (95% CI: 22.5, 38.0) reported injecting drugs two or more times per day in the last 6 months, 38.2% (95% CI: 30.7, 45.7) injected with a used needle at least once in the last 6 months, and 21.7% (95% CI: 14.6, 28.7) had engaged in Bluetooth (i.e., when an individual injects the blood of another person who had just injected a drug in order to share the high) at least once in their life. For a question that participants could select more than one response to, 92.5% (95% CI: 87.1, 98.8) reported that the most common drug they injected in the 6 months preceding the survey was Tie White Heroin, whereas a lower percentage cited Promethazine (8.8%, 95% CI: 2.7, 15.1), Artane (Trihexyphenidyl) (5.0%, 95% CI: 1.7, 8.3), and Benylin/Codein (3.9%, 95% CI: 0.6, 7.3). Due to injecting drugs, over half had been rejected by family (50.5%, 95% CI: 42.8, 58.2), 8.0% (95% CI: 3.8–12.3) reported being treated unfairly or denied care by healthcare practitioners (HCPs), 31.0% (95% CI: 23.6–38.4) avoided healthcare due to fear of someone discovering they inject, 20.2% (95% CI: 13.4, 26.7) had lost a job, and 14.4% (95% CI: 8.1, 20.5) have been arrested. Few were aware of drug treatment programs (including outpatient, inpatient, residential, detox, and methadone maintenance programs) (15.9%, 95% CI: 10.9, 20.8).

10.1371/journal.pone.0323919.t003Injection drug use and history of stigma, discrimination, and criminalization—Livingstone, Lusaka, and Ndola, Zambia, 2021.
Livingstone Lusaka Ndola
Sample Size n = 235 n = 349 n = 259
Sample Population Sample Population Sample Population
n % % (95% CI) n % % (95% CI) n % % (95% CI)
Median age when started injecting drugs (IQR) 19.0 (17.0, 22.0) 19.0 (17.0, 23.0) 21.0 (18.0, 25.0)
Age category when started injecting drugs
 <15 19 8.1 5.7 (3.0-8.4) 12 3.4 2.2 (0.8-3.7) 7 2.7 2.3 (0.6-4.0)
 15-19 116 49.4 50.0 (41.0-59.0) 172 49.4 51.8 (44.5-59.1) 101 39.0 36.5 (28.4-44.5)
 20-24 52 22.1 24.8 (17.2-32.3) 104 29.9 27.7 (21.7-33.7) 82 31.7 34.4 (27.0-41.7)
 ≥ 25 48 20.4 19.5 (13.5-25.5) 60 17.2 18.3 (12.6-23.9) 69 26.6 26.8 (19.4-34.2)
Median duration of injection drug use (IQR), years 4.0 (2.0, 6.0) 5.0 (3.0, 7.0) 6.0 (3.0, 10.0)
Last time injected drugs?
 Today/yesterday 122 51.9 46.5 (38.5-54.5) 184 52.7 44.6 (37.6-51.6) 47 18.2 16.6 (11.1-22.0)
 Within last week 92 39.1 43.3 (35.5-51.2) 142 40.7 49.3 (41.7-56.8) 125 48.4 46.8 (38.1-55.5)
 Within last month or longer 21 8.9 10.2 (5.7-14.5) 23 6.6 6.1 (2.1-10.2) 86 33.3 36.6 (27.5-45.8)
How often were drugs injected in the last 6 months?
 2 or more times per day 79 33.6 30.1 (22.5-38.0) 120 34.4 29.3 (23.0-35.5) 21 8.1 5.9 (2.6-9.1)
 Once per day or less 126 53.6 55.5 (47.2-63.4) 135 38.7 36.4 (29.9-42.9) 62 23.9 18.3 (12.4-24.1)
 Once per week or less 30 12.8 14.4 (9.3-19.6) 94 26.9 34.3 (26.9-41.8) 176 68.0 75.8 (69.0-82.8)
Most common drugs injected in the last 6 months?
 Tie White (Heroin) 222 94.5 92.5 (87.1-98.8) 333 95.4 95.8 (93.5-98.2) 75 29.0 28.3 (19.9-36.6)
 Dirty Drug/Voloo (Mixed Heroin) 2 0.9 0.4 (0.0-0.8) 263 75.4 76.4 (70.2-82.5) 19 7.3 6.4 (2.3-10.5)
 Artane(Trihexyphenidyl) 10 4.3 5.0 (1.7-8.3) 18 5.2 4.5 (1.9-7.2) 177 68.3 68.2 (59.6-76.7)
 Blue Marsh (Promethazine) 15 6.4 8.8 (2.7-15.1) 20 5.7 5.8 (2.4-9.3) 160 61.8 60.1 (50.9-69.2)
 Nyerere (Benylin/Codein) 7 3.0 3.9 (0.6-7.3) 22 6.3 4.3 (2.1-6.4) 92 37.0 38.1 (30.4-46.0)
 Ashtone Powder (Cocaine) 1 0.4 0.4 (0.0-0.9) 64 18.3 19.8 (13.7-25.9) 29 11.2 11.7 (5.9-17.4)
How often were drugs injected with a used needle in the last 6 months?
 Never 73 31.1 26.4 (20.5, 32.5) 122 35.0 35.7 (28.8, 42.7) 54 20.8 23.9 (16.5, 31.3)
 At least once 94 40.0 38.2 (30.7, 45.7) 48 13.8 13.5 (9.0, 18.1) 126 48.6 47.4 (39.3, 55.5)
 No answer 68 28.9 35.4 (27.1, 43.5) 179 51.3 50.8 (43.9, 57.5) 79 30.5 28.7 (21.7, 35.8)
Ever engaged in Bluetooth? 48 20.4 21.7 (14.6-28.7) 17 4.9 7.2 (2.6-11.7) 32 12.4 10.5 (6.2-14.8)
Rejected by family for injecting drugs 138 58.7 50.5 (42.8-58.2) 234 67.0 67.1 (60.9-73.4) 78 30.1 31.7 (23.9-39.5)
Treated unfairly/denied care by HCPs because you inject drugs 19 8.1 8.0 (3.8-12.3) 67 19.2 20.2 (14.8-25.5) 43 16.6 18.6 (12.5-24.7)
Avoided healthcare because of fear someone might discover they inject drugs 80 34.0 31.0 (23.6-38.4) 159 45.6 45.2 (37.9-52.4) 137 52.9 52.8 (44.5-61.2)
Lost a job due to injecting drugs 44 18.7 20.2 (13.4-26.7) 84 24.1 25.7 (19.3-32.1) 36 13.9 16.9 (11.0-22.7)
Ever arrested for injecting drugs 28 11.9 14.4 (8.1-20.5) 133 38.1 37.6 (31.5-43.9) 28 10.8 11.5 (6.5-16.5)
Aware of any drug treatment programs* 42 17.9 15.9 (10.9-20.8) 145 41.5 41.3 (34.5-48.2) 51 19.7 20.0 (13.2-26.7)

Population estimates and 95% Confidence Intervals are weighted using Gile’s SS estimator, whereas sample estimates are unweighted. CI: Confidence Interval. IQR: Interquartile Range. *Includes outpatient, inpatient, residential, detox, and methadone maintenance drug treatment programs.

 Lusaka.

In Lusaka, the median age when PWID started injecting was 19.0 years (IQR: 17.0–23.0) and they had injected for a median duration of 5.0 years (IQR: 3.0–7.0). Almost half (44.6%, 95% CI: 37.6, 51.6) had injected within a day of the survey, 29.3% (95% CI: 23.0, 35.5) injected drugs two or more times per day in the last 6 months, 13.5% (95% CI: 9.0, 18.1) injected with a used needle at least once in the last 6 months, and 7.2% (95% CI: 2.6, 11.7) engaged in Bluetooth. Tie White Heroin was again the most commonly reported drug injected in the previous 6 months (95.8%, 95% CI: 93.5, 98.2), with a lower percentage reporting Mixed Heroin (76.4%, 95% CI: 70.2, 82.5), Cocaine (19.8%, 95% CI: 13.7, 25.9), and Promethazine (5.8%, 95% CI: 2.4, 9.3) as their injectable drug of choice. About two-thirds had been rejected by family (67.1%, 95% CI: 60.9, 73.4), 20.2% (95% CI: 14.8, 25.5) had been treated unfairly/denied care by HCPs, nearly half avoided healthcare (45.2%, 95% CI: 37.9, 52.4), a quarter lost a job (25.7%, 95% CI: 19.3, 32.1), and 37.6% (95% CI: 31.5, 43.9) had been arrested because they injected drugs. Approximately four in ten were aware of drug treatment programs (41.3%, 95% CI: 34.5, 48.2).

 Ndola.

The median age PWID in Ndola started injecting was 21.0 years (IQR: 18.0–25.0) and they had injected for a median of 6.0 years (IQR: 3.0–10.0). Almost a fifth (16.6%, 95% CI: 11.1, 22.0) had injected drugs within a day of the survey, 5.9% (95% CI: 2.6, 9.1) had injected two or more times a day for the last six months, 47.4% (95% CI: 39.3, 55.5) injected with a used needle at least once in the last 6 months, and 10.5% (95% CI: 6.2, 14.8) had engaged in Bluetooth. Artane (Trihexyphenidyl) was the most commonly injected drug (68.2%, 95% CI: 59.6, 76.7) in the previous 6 months, followed by Promethazine (60.1%, 95% CI: 50.9, 69.2), Benylin/Codein (38.1%, 95% CI: 30.4, 46.0), and Tie White Heroin (28.3%, 95% CI: 19.9, 36.6). Nearly a third had been rejected by family (31.7%, 95% CI: 23.9, 39.5), 18.6% (95% CI: 12.5, 24.7) had been treated unfairly/denied care by HCPs, 52.8% (95% CI: 44.5, 61.2) avoided healthcare, 16.9% (95% CI: 11.0, 22.7) lost a job, and 11.5% (95% CI: 6.5, 16.5) had been arrested because of injecting drugs. A fifth were aware of drug treatment programs (20.0%, 95% CI: 13.2, 26.7).

 HIV prevalence, viral load suppression, testing, outreach, and prevention awareness Livingstone.

HIV prevalence among PWID in Livingstone was 11.9% (95% CI: 7.3, 16.5) (Table 4). Among PWID living with HIV, 70.8% (95% CI: 56.8, 85.1) were virally suppressed (< 1000 copies/mL). Of all PWID, 3.0% (95% CI: 0.6, 5.3) had active syphilis, and most had previously tested for HIV (91.8%, 95% CI: 87.4, 96.2). However, among those, 26.0% (95% CI: 20.0, 32.1) most recently tested more than a year before the survey. Almost two thirds (63.3%, 95% CI: 54.9, 71.5) received HIV information from a peer educator and/or outreach worker in their lifetime. For a question that participants could select more than one response to, 78.7% (95% CI: 71.9, 85.7) preferred getting HIV information from HCPs, whereas a lower percentage cited a preference for getting their information from peer educators and/or outreach workers (47.2%, 95% CI: 39.3, 55.0), friends (39.3%, 95% CI: 31.3, 47.3), internet (11.9%, 95% CI: 6.5, 17.3), television (8.5%, 95% CI: 4.5, 12.4), and/or radio (2.9%, 95% CI: 0.6, 5.3). Almost two-thirds of PWID (63.9%, 95% CI: 55.0, 72.9) heard of pre-exposure prophylaxis (PrEP). Of those, 16.6% (95% CI: 9.6, 23.8) had taken PrEP. Of those who had taken PrEP, 48.4% (95% CI: 32.9, 64.7) were on it at the time of the survey. The majority of PWID (93.6%, 95% CI: 88.3, 98.8) knew they were at risk for acquiring HIV by injecting with a used needle. The number of Hepatitis B and C cases among PWID was too low to report for Livingstone (≤5) and so were suppressed in Table 4 for confidentiality purposes.

10.1371/journal.pone.0323919.t004HIV prevalence, viral load suppression, biomarker testing, outreach, PrEP, and prevention awareness—Livingstone, Lusaka, and Ndola, Zambia, 2021.
Livingstone Lusaka Ndola
Sample Size n = 235 n = 349 n = 259
Sample Population Sample Population Sample Population
n % % (95% CI) n % % (95% CI) n % % (95% CI)
HIV Prevalence 32 13.6 11.9 (7.3-16.5) 26 7.4 7.3 (4.5-10.2) 52 20.1 21.9 (14.5-29.3)
 Viral Load Suppression ꝉ (of those who are HIV-positive) 23 71.9 70.8 (56.8-85.1) 9 34.6 33.1 (17.7-48.4) 29 55.8 58.0 (27.8-88.3)
Active Syphilis Prevalence 9 3.8 3.0 (0.6-5.3) 16 4.6 4.5 (2.1-7.0) 26 10.0 11.1 (5.3-16.8)
 HIV/Active Syphilis Co-infection (of those with active syphilis) * * * * * * 15 57.7 49.3 (24.5-75.3)
Previously tested for HIV 215 91.5 91.8 (87.4-96.2) 282 80.8 79.5 (74.2-84.9) 228 88.0 87.0 (81.0-93.1)
Never tested for HIV 20 8.5 8.2 (3.8-12.5) 67 19.2 20.5 (15.2-25.7) 31 12.0 13.0 (7.5-18.4)
 Did not test because they did not feel at risk * * * 16 23.9 23.6 (4.6-42.6) 10 32.3 36.8 (12.5-62.0)
 Did not test because they feared a positive result * * * 14 20.9 22.8 (7.2-38.2) 9 29.0 29.9 (9.9-50.0)
Timing of last HIV test
 In the last 6 months 111 47.2 51.0 (43.0-59.0) 108 30.9 25.5 (20.2-31.0) 105 40.5 44.2 (35.7-52.6)
 Between 7–12 months 32 13.6 14.8 (9.5-20.1) 49 14.0 16.8 (11.2-22.3) 35 13.5 10.3 (5.4-15.2)
 More than 12 months 72 30.6 26.0 (20.0-32.1) 124 35.5 36.5 (30.3-42.7) 87 33.6 32.4 (25.2-39.6)
Received HIV messaging from peer educator or outreach worker in their lifetime 147 62.6 63.3 (54.9-71.5) 196 56.2 55.9 (48.6-63.3) 152 58.7 58.5 (50.6-66.4)
Preferred source for HIV information
 Health care providers 188 80.0 78.7 (71.9-85.7) 297 85.1 90.0 (86.5-93.2) 214 82.6 84.1 (78.3-90.1)
 Peer educator/outreach worker 101 43.0 47.2 (39.3-55.0) 162 46.4 47.1 (40.3-54.0 76 29.3 31.0 (22.7-39.3)
 Internet 24 10.2 11.9 (6.5-17.3) 32 9.2 9.1 (5.1-13.0) 13 5.0 5.7 (1.6-9.8)
 Television 27 11.5 8.5 (4.5-12.4) 118 33.8 35.9 (28.8-42.9) 19 7.3 5.0 (2.5-6.5)
 Radio 6 2.6 2.9 (0.6-5.3) 188 53.9 56.6 (49.6-63.5) 18 6.9 6.5 (2.8-10.2)
 Friends 75 31.9 39.3 (31.3-47.3) 118 33.8 37.3 (30.2-44.4) 30 11.6 13.8 (8.1-19.4)
Ever heard of PrEP 152 67.6 63.9 (55.0-72.9) 63 19.0 16.0 (11.3-20.8) 116 49.4 53.3 (43.9-62.8)
 Taken PrEP (of those who have heard of it) 24 15.8 16.6 (9.6-23.8) 10 15.9 15.8 (5.2-26.3) 29 25.0 23.0 (8.9-37.0)
 Currently on PrEP (of those who have taken it) 11 45.8 48.4 (32.9-64.7) 6 60.0 71.2 (45.4-98.2) 22 75.9 70.3 (53.2-87.1)
Aware can get HIV by injecting with used needle 219 93.2 93.6 (88.3-98.8) 332 95.1 94.9 (92.0-97.7) 250 96.5 96.7 (94.5-98.9)
Hepatitis B (HBsAg) Prevalence * * * 16 4.6 5.0 (1.7-8.2) 10 3.9 2.2 (0.7-3.7)
Hepatitis C prevalence‡ * * * * * * * * *

Population estimates and 95% Confidence Intervals are weighted using Gile’s SS estimator, whereas sample estimates are unweighted. CI: Confidence Interval. IQR: Interquartile Range. HBsAg: Hepatitis B surface antigen. *Suppressed due to number being ≤ 5. ꝉ Viral Load Suppression (VLS) is < 1000 copies/mL. ‡There were five HCV cases across all three sites.

 Lusaka.

HIV prevalence among PWID in Lusaka was 7.3% (95% CI: 4.5, 10.2), of which 33.1% (95% CI: 17.7, 48.4) were virally suppressed. Of all PWID, 4.5% (95% CI: 2.1, 7.0) had active syphilis, 79.5% (95% CI: 74.2, 84.9) had tested for HIV; but of those, 36.5% (95% CI: 30.3, 42.7) had tested over a year before the survey. Of those who never tested, 23.6% (95% CI: 4.6, 42.6) did not test because they did not feel at risk whereas 22.8% (95% CI: 7.2, 38.2) did not test because they were afraid of receiving a positive result. The majority (90.0%, 95% CI: 86.5, 93.2) preferred getting HIV information from HCPs, whereas a lower percentage preferred the radio (56.6%, 95% CI: 49.6, 63.5), peer educators/outreach workers (47.1%, 95% CI: 40.3, 54.0), friends (37.3%, 95% CI: 30.2, 44.4), and/or television (35.9%, 95% CI: 28.8, 42.9). Of all PWID, 16.0% (95% CI: 11.3, 20.8) heard of PrEP, and 15.8% (95% CI: 5.2, 26.3) of those had taken it. Of those who had taken PrEP, 71.2% (95% CI: 45.4, 98.2) were on it at the time of the survey. Lastly, 94.9% (95% CI: 92.0, 97.7) were aware injecting with used needles posed an HIV risk. Prevalence of Hepatitis B was 5.0% (95% CI: 1.7, 8.2) and the prevalence of Hepatitis C was too low to report (≤5).

 Ndola.

HIV prevalence among PWID in Ndola was 21.9% (95% CI: 14.5, 29.3) and 58.0% (95% CI: 27.8, 88.3) of those were virally suppressed. Active syphilis prevalence was 11.1% (95% CI: 5.3, 16.8) and 49.3% (95% CI: 24.5, 75.3) of those were co-infected with HIV. The majority of PWID (87.0%, 95% CI: 81.0, 93.1) had been tested for HIV, but 32.4% (95% CI: 25.2, 39.6) of those tested more than a year before the survey. Among PWID who had never been tested, 36.8% (95% CI: 12.5, 62.0) did not test because they did not feel at risk and 29.9% (95% CI: 9.9, 50.0) did not test because they feared a positive result. Over half of all PWID (58.5%, 95% CI: 50.6, 66.4) had received HIV counseling from a peer educator or outreach worker. Most (84.1%, 95% CI: 78.3, 90.1) stated a preference for receiving HIV information from HCPs. Please see Table 4 for percentages who preferred other sources. Over half (53.3%, 95% CI: 43.9, 62.8) heard of PrEP and 23.0% (95% CI: 8.9, 37.0) of those had taken it. Of those who had taken PrEP, 70.3% (95% CI: 53.2, 87.1) were on it at the time of the survey. Most PWID (96.7%, 95% CI: 94.5, 98.9) knew they could get HIV from used needles. Hepatitis B prevalence was 2.2% (95% CI: 0.7, 3.7) and Hepatitis C prevalence was too low to report (n ≤ 5).

 Population-level 95-95-95 progress Livingstone.

Of all HIV-positive PWID in Livingstone, 70.7% (95% CI: 55.4, 85.0) were aware of their serostatus. Of those, 100% were on ART, and 100% of those had achieved VLS (Fig 1).

10.1371/journal.pone.0323919.g001Progress towards UNAIDS 95-95-95 targets among PWID living with HIV in Livingstone, Lusaka, and Ndola, Zambia, 2021.

Population estimates and 95% Confidence Intervals are weighted using Gile’s SS estimator. ART status is viral load adjusted (<200 copies/mL). VLS is defined as <1000 copies/mL. Conditional percentages are shown.

 Lusaka.

Among HIV-positive PWID in Lusaka, 66.0% (95% CI: 49.3, 82.2) were aware of their serostatus. Of those, 75.7% (95% CI: 51.1, 99.9) were on ART and 66.3% (95% CI: 42.1, 90.9) of those had achieved VLS.

 Ndola.

Of the HIV-positive PWID in Ndola, 60.2% (95% CI: 44.1, 76.0) were aware of their serostatus, 100% of those were on ART, and 90.2% (95% CI: 82.2, 98.3) of those on ART had achieved VLS.

 Discussion

Our results summarize the first probability-based BBS among PWID in Zambia and include information on HIV, VL, syphilis, HBV, HCV, and progress towards the UNAIDS 95-95-95 targets. Also presented are key sociodemographic and sexual history patterns, along with findings on injection drug use, stigma, discrimination, and criminalization that showcase commonalities and variations across sites. Livingstone’s high HIV prevalence, low HIV risk perception, young PWID population, higher prevalence of forced sex, and lower awareness of drug treatment programs present unique challenges. Lusaka has lower HIV prevalence but a significant gap in ART uptake and VLS, very low awareness of PrEP, and demonstrates a high proportion of male PWID, homelessness, and a substantial number forced to have sex. Ndola’s slightly older PWID population includes a much larger female presence and larger prevalence of those who inject with used needles, which may explain its especially high HIV prevalence and subsequent need for expanded preventive interventions. The site-specific differences revealed by this survey contribute to the broader discourse on HIV among PWID in SSA and emphasize the importance of community-specific approaches in addressing the diverse challenges faced by PWID in different contexts.

Livingstone

HIV prevalence among PWID in Livingstone (11.9%, 95% CI: 7.3, 16.5) was consistent with HIV prevalence among those 15 years and older in the general population of Zambia’s Southern province (13.2%), where Livingstone is located [20]. However, it is higher than the prevalence in 20–24-year-old women (5.9%) and men (1.8%) of the country-wide general population, which is roughly the same age range as our sample [20]. CIs were wide so results should be interpreted with caution, but findings indicate the 2nd and 3rd 95 targets were met among PWID in Livingstone. However, their progress toward the 1st 95 was well below the target. Several issues could have contributed to this observation. Almost a third of Livingstone’s PWID who had previously tested for HIV had tested more than a year prior to the survey. WHO guidelines state that PWID should be tested every year [48], whereas Zambian guidelines state that persons should be retested after instances of having shared injecting equipment [33] and almost four in ten PWID in Livingstone injected with used needles at least once in the six months preceding the survey. Stigma could have played a role in this community delaying or avoiding testing as well, since almost one-third said they avoided healthcare due to fear someone might discover they inject drugs.

 Lusaka

PWID in Lusaka had an HIV prevalence (7.3%, 95% CI: 4.5, 10.2) slightly higher than women (5.9%) and men (1.8%) of Zambia’s general population of the same age group but lower than the all-age prevalence in the broader Lusaka province’s general population (14.4%) [20]. It may have been lower than the general population all-age prevalence due to a combination of the young age and preponderance of males (97.4%, 95% CI: 96.0, 98.9) in Lusaka’s PWID population. Compared to the other two cities, Lusaka showed relatively poor progress toward all three 95 targets. It had the lowest percentage of PWID who had ever been tested for HIV, and of those, over a third were not tested within the previous year. Compared to Livingstone (31.0%, 95% CI: 23.6, 38.4), a higher proportion of PWID in Lusaka (45.2%, 95% CI: 37.9, 52.4) avoided healthcare due to fear of someone discovering they inject drugs, and almost 8.0 percentage points less of PWID had been reached by peer educators and/or outreach workers. About 40% had been arrested for injection drug use, which is part of an overall shift within Zambia’s capital toward punitive, rather than rehabilitative drug enforcement policies, particularly among young people [49]. One-fifth of Lusaka PWID had been treated unfairly and/or outright denied care by HCPs due to injection drug use. Their relatively low rate of HIV testing compared to Livingstone and Ndola, low rate of recent testing, high frequency of healthcare avoidance, unfair treatment or denial of care by HCPs, low number of outreach encounters, and high arrest rates all could have contributed to Lusaka PWID’s lower performance toward the UNAIDS goals.

 Ndola

HIV prevalence among PWID in Ndola (21.9%, 95% CI: 14.5, 29.3) was higher than that of the general all-age population in the Copperbelt province (11.9%) [20], where Ndola is located. It was also higher than women (12.0%) and men (3.1%) in the 25–29-year-old age group of the Zambian general population [20]. The median age of PWID from Ndola was 28.0 years. Prevalence of active syphilis in Ndola (11.1%) was more than double the prevalence of the other two cities, and of those with active syphilis, nearly half were HIV-positive. Progress toward the 1st 95 was low (60.2%). Like Lusaka, about a third of PWID who had ever been tested for HIV had last been tested more than a year before the survey. Risk perception was even lower in Ndola than the other two sites: almost 40% of those never tested for HIV said their reason for not testing was because they felt they were not at risk and almost half of PWID in Ndola admitted to injecting with a used needle at least once in the 6 months preceding the survey despite almost all knowing they can get HIV by injecting with a used needle. Once aware of their status, PWID in Ndola seemingly did not have a problem initiating ART, but only 90.2% of those on ART achieved VLS, which indicates that adherence to ART or the prescribing of proper ART regimens and follow-up may be a problem. Women comprised nearly 30% of the sample in Ndola compared to over 15% in Livingstone and just over 2% in Lusaka, which likely contributed to the high prevalence of active syphilis observed. Female PWID typically experience higher rates of sexually transmitted infections than male PWID [50]. It would be advisable for future inquiries to ascertain if there are reasons other than the higher share of female PWID as to why HIV and active syphilis prevalence is so high in Ndola.

 Implications for programs and policy

While there were similarities across the three sites, there were notable differences as well. This granularity in results would not have been detected with a national-level survey, provincial-level survey, or if our site-specific data had been aggregated. The community-level data obtained from this first ever BBS among PWID in Livingstone, Lusaka, and Ndola establish an understanding of where specific gaps exist regarding 95-95-95 progress and provide insights into what may be contributing to these gaps. Local data like this can help stakeholders better design and implement context-driven interventions meant to maximize the number of PWID who are aware of their HIV serostatus, on ART, and who have achieved VLS.

All three sites were well below the 1st 95 target regarding serostatus awareness. A positive finding was that over 90% of all PWID across sites were aware HIV could be transmitted by sharing needles. A 2015 study in Mwanza, Tanzania showed that only 64.1% of PWID knew sharing needles posed an HIV risk [51]. The high level of awareness regarding the harms of needle sharing contrasts with the appreciable share of PWID in Livingstone and Ndola who reported injected with used needles. It also contrasts with a large portion of PWID in Lusaka and Ndola who had never tested for HIV due to feeling they were not at risk, and that roughly a third of those who had tested for HIV did so more than a year before the survey. Also, approximately only a fifth of PWID across all sites who were aware of PrEP had ever taken it. In Livingstone, Lusaka, and Ndola the preferred source of HIV information was HCPs. The aforementioned findings highlight a potential opportunity for HCPs to review national guidelines and update them as necessary to meet the unique gaps and needs of PWID. Additional training for HCPs that help them initiate discussions with patients on why they are not testing more often and/or why they do not feel at risk may be helpful. Other potential reasons for lack of testing and lack of recent testing are the commonly reported issues of avoiding healthcare in the first place due to fear of injection drug use discovery and that PWID who do visit HCPs may not be disclosing their drug use, making it impossible for providers to give injection drug use-specific counseling. Local health departments could ensure the existence or expansion of in-service training for HCPs that includes a robust curriculum on the most up-to-date HIV treatment, prevention, and counseling guidelines, sensitization training on key populations and harm reduction, along with improved outreach efforts as well [48]. In addition, only about 60% of all PWID had been counseled by peer educators and/or outreach workers about HIV awareness and prevention. Better counseling by HCPs and an increased number of quality encounters with HIV outreach workers and peer educators may increase HIV risk perception, knowledge profiles, and outcomes [52–54]. It may be needed for peer educators and outreach workers to be more proactive about creating new connections with PWID reluctant to seek out services on their own. HCPs, peer educators, and outreach workers should strive to work together to educate PWID about HIV, whereas HCPs and case managers may be able to navigate them more effectively through the HIV prevention and care continuum. To decrease the concerns PWID have of their drug use being discovered, partnerships can be created between interest holders (e.g., PEPFAR, Global Fund) and the Zambian MoH to increase the number of PWID friendly service providers and community-based HIV facilities (i.e., safe environments with decreased threat of stigma, discrimination, or having injection drug use reported to the police [12,55,56]) where positive support and education networks among peers, HCPs, and outreach personnel can be fostered [52,57–59]. Preventive resources like PrEP can be efficiently offered in these facilities as well [59], along with OAMT [60] and NSPs. Results from the 2021 BBS have already propelled the establishment of a PWID task force with representation from government and non-governmental agencies that is working to establish MAT clinics while the police and Home Affairs Ministry offer basic rehabilitative services to the public in Lusaka. The PWID task force is also in the process of creating national policy regarding methadone approval in Zambia. In preparation for its approval, University Teaching Hospital in Lusaka is preparing space for a MAT clinic, but at the current time is only offering services like HIV testing, treatment, and wound care to attract PWID clientele for when OAMT becomes approved. Again, OAMT and NSPs, if approved, would likely serve as a strong facilitator to getting PWID into the HIV testing and treatment pathway. To this end, OAMT may be most impactful in Livingstone and Lusaka where Heroin is by far the most commonly reported drug injected, as opposed to Ndola where Trihexyphenidyl is most common; whereas NSPs may be most impactful in Livingstone and Ndola, where PWID reported higher rates of injecting with a used needle than Lusaka.

The low HBV and HCV prevalence across all three sites is encouraging. Active HBV/HCV surveillance and testing should continue within the high-risk PWID community, while consideration can be given to streamlined treatment models, such as point-of-service care [61].

 Limitations

Independent associations between plausible predictive factors and the 95 target outcomes (e.g., prevalence of HIV awareness, on ART, and VLS) were explored. Unfortunately, sample sizes were very small for certain indicators which resulted in CIs and standard errors too large to convey meaningful information. Therefore, these results were not reported. Most PWID said they preferred to receive HIV information from HCPs, but more detailed data on those interpersonal interactions were not available, such as whether HCPs created a PWID-friendly environment or not, how comfortable they made it for PWID to disclose injection drug use status, what kind of proactive outreach they may have done to contact PWID, what type of information HCPs typically gave to PWID after becoming aware of their HIV status, problems that may have occurred in prescribing the full correct ART regimen, and/or other barriers such as distance to health facilities. Our variable on awareness of drug treatment programs (including outpatient, inpatient, residential, detox, and methadone maintenance therapy) is of limited value since OAMT and NSPs are currently not available in Zambia, however the low awareness observed indicates work must be done to increase awareness on the benefits of these programs if they are to be maximally successful if and when they are approved. Data on issues like HIV drug resistance, stockouts, distance to facilities, guidance on same day ART initiation, and other facilitators and barriers that could have impacted progress toward the 95-95-95 targets were not available. This survey also took place during the COVID Omicron wave which could have impacted network size, weighting, and access to HIV-related services [62]. Lastly, this is a cross-sectional survey that is subject to recall bias [63] and social desirability bias [64], especially since many questions were regarding sensitive issues about injection drug use and sexual and reproductive health history.

 Conclusion

This survey produced a representative sample of PWID in Livingstone, Lusaka, and Ndola, Zambia and is a foundation for understanding HIV vulnerabilities in this population. It demonstrated that PWID in all three sites were well short of achieving the 1st UNAIDS 95 target. Achievement toward the 2nd and 3rd targets were variable across sites. Only about 60% of PWID had been in contact with peer educators and/or outreach workers, awareness of drug treatment programs was low, needle sharing was common, many PWID who had been tested for HIV did so more than a year before the survey, and an appreciable number of respondents avoided healthcare due to fear of someone discovering their injection drug use. Improved counseling by HCPs; the establishment of community-based PWID-friendly HIV, OAMT, and NSP clinics that can serve as another link for helping PWID access HIV testing; and better coordination between HCPs, peer educators, and outreach workers in proactively contacting, counseling, and guiding PWID through the HIV prevention and care continuum may help improve these outcomes.

The geographical nuances to barriers and characteristics of HIV prevention, awareness, and care uncovered in this survey contribute to the larger discussion on HIV in SSA and emphasize the importance of site-specific approaches to addressing the unique challenges faced by PWID. Insights gleaned from this survey can be used to justify increased support and funding for expanded HIV interventions among PWID in Zambia. This survey also indicates that strengthening PWID-specific programs can advance progress toward the overall UNAIDS targets and better ensure the well-being of this marginalized population.

We extend our gratitude to all participants for dedicating their time and providing invaluable feedback. Our sincere appreciation goes to our partners, and we acknowledge the significant contributions of the Zambia Survey Advisory Group, which includes representatives from CDC, NAC, TDRC, ICAP, and the Zambia Key Population Consortium.

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 10.1371/journal.pone.0323919.r002 Decision Letter 0 Scheibe Andrew Academic Editor 2025 Andrew Scheibe This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication. Submission Version 0

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PONE-D-24-29546Local data for local programming: Results from an HIV biobehavioral survey among people who inject drugs in Livingstone, Lusaka, and Ndola, Zambia, 2021PLOS ONE

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Journal requirements: When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf" 2. Please include a complete copy of PLOS’ questionnaire on inclusivity in global research in your revised manuscript. Our policy for research in this area aims to improve transparency in the reporting of research performed outside of researchers’ own country or community. The policy applies to researchers who have travelled to a different country to conduct research, research with Indigenous populations or their lands, and research on cultural artefacts. The questionnaire can also be requested at the journal’s discretion for any other submissions, even if these conditions are not met.  Please find more information on the policy and a link to download a blank copy of the questionnaire here: https://journals.plos.org/plosone/s/best-practices-in-research-reporting. Please upload a completed version of your questionnaire as Supporting Information when you resubmit your manuscript. 3. We note that the grant information you provided in the ‘Funding Information’ and ‘Financial Disclosure’ sections do not match.  When you resubmit, please ensure that you provide the correct grant numbers for the awards you received for your study in the ‘Funding Information’ section. 4. Thank you for stating the following financial disclosure:  [This activity was supported by the US President’s Emergency Plan for AIDS Relief (PEPFAR) (https://www.state.gov/pepfar/) through the US Centers for Disease Control and Prevention (CDC) under the terms of cooperative agreement “Supporting sustainable surveillance systems among key populations and support the Government of Zambia to improve HIV-related services for KPs” (Prime Award No. 1NU2GGH002056). The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the funding agencies. ].  Please state what role the funders took in the study.  If the funders had no role, please state: ""The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."" If this statement is not correct you must amend it as needed. Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf. 5. We note that you have indicated that there are restrictions to data sharing for this study. For studies involving human research participant data or other sensitive data, we encourage authors to share de-identified or anonymized data. However, when data cannot be publicly shared for ethical reasons, we allow authors to make their data sets available upon request. For information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions.  Before we proceed with your manuscript, please address the following prompts: a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially identifying or sensitive patient information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., a Research Ethics Committee or Institutional Review Board, etc.). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent. b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. Please see http://www.bmj.com/content/340/bmj.c181.long for guidelines on how to de-identify and prepare clinical data for publication. For a list of recommended repositories, please see https://journals.plos.org/plosone/s/recommended-repositories. You also have the option of uploading the data as Supporting Information files, but we would recommend depositing data directly to a data repository if possible. Please update your Data Availability statement in the submission form accordingly.

6. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

Thank you for submitting this paper. It is great to have information on PWID from Zambia in the literarture. In addition to the feedback provided by the reviews:

1. Introduction (lines 82 - 84). The objective does not mention assessment or presentation of results around syphylis, HBV or HCV (STI and BBV), so consider noting these too.

2. Introduction. The provision and availability of needle and syringe programmes (NSP) and opioid agonist maintenance therapy (OAMT) and treatment of stimulant dependence in Zambia should be briefly described.

3. Methods (lines 92). Insert a short description about each study site for readers who may not be familiar with Zambia.

4. Findings. The findings section (notably descriptions) is a bit long in parts. Aim to focus on key findings, and reduce some descriptions of socio demographic characteristics, and refer to the table.

5,.Findings. Table 1. Insert the % for all rows, where relevant (currently only done for some).

6. Findings. Unless I missed it, I did not see the description of the type of drugs injected. This is critical to assess risk, prevention and interventions.

7. Table 3. Median duration of injecting. Check the median and p25 and p75 - I would expect the median to lie between these, but does not seem to be the case (e.g., Ndola median is 3.0 years, but IQR is 6 - 10 year).

8. Insert n for anti-HCV results and HCV PCR for sample in table and findings description.

9. Findings around awareness of OAMT - this would only apply to people with opioid dependence, but it is not clear what drugs people injected. Also, Table 3 notes " aware of any drug treatment programs" - this is too broad to reflect insights into OAMT. So if questions on OAMT were asked, please include. If not, this could be noted in the limitations.

10. Findings. Why no findings of needle reuse/ sharing? This is the most important risk factor for PWID? (Unless I missed it). This is key to include, as it is a UNAIDS GAM indicator. Please include these variables.

11. Discussion. Among PWID, the primary HIV prevention interventions are NSP and OAMT, these should be foregrounded. These interventions are more important for PWID than PrEP, yet there is much emphasis on PrEP. Similarly, the implications for policy and practice, NSP and OAMT need to be much higher priorities than PrEP, but the framing does not align with emphasis on the issues that are particular to PWID. There is mention of MAT clinics, but what about NSP? This is critical, as many African countries are resistant to NSP, but without NSP HIV prevention interventions for PWID will fail to be be effective.

12. Discussion. The low HBV and (HCV?) prevalence is encouraging, and the implication for policy could also be to continue active surveillance and testing in these high risk groups to control the epidemic, and have access to HCV treatment early, before there is an epidemic, like is happening in other countries (e.g., South Africa).

13. Conclusion. Reflection on the important gap of NSPs seems to be missing. NSPs should be framed as being the link to access HTS and then enter the treatment pathway.

We look forward to receiving your revised manuscript.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: No

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The details from this survey are nicely presented, and provide a rich, detailed biobehavioural insights into PWID risks in Zambia. I think the manuscript can however be too descriptive in parts, and some statistical analysis would complement the data nicely.

Abstract

Lines 38-39 – don’t need to mention both HIV and HIV viral load testing.

Results – find the (1st 95) confusing, same for 2nd and 3rd – link to targets unclear. For those less familiar with HIV targets, it may be helpful to say what the targets are when they’re being discussed (and elsewhere in the paper).

Manuscript

Line 96 – the ‘prevalence of VLS’ may be better described as the proportion of people living with HIV with VLS

Lines 102-103 – not sure the data on sample size calculations are needed if they were missed by such a large margin. If the authors want to include the calculation, more details are needed on the factors limiting study size (costs/ time constraints etc).

Lines – pre-test counselling for HIV/syphilis is mentioned, was this also done for HBV/HCV, or are there no national guidelines on this?

Line 142 – Might be useful to state where the Tropical Diseases Research Centre (TDRC) laboratory is based

Results lines 196-320, Tables 2-4 – this section contains a large amount of data in well-presented tables but overall, is very descriptive with the paragraphs describing the data from each table for each location. I would like to see more comparison between the sites in this section – ie were people younger/older at one site? Were there different risk factors at each site? Was one site better at getting PWID onto ART? Some of this is mentioned in the discussion but is perhaps better placed in the results section. Some statistics to highlight differences between the sites would be informative and help to summarise the data.

Discussion – it would be useful to get some idea of how widespread injection drug use is in Zambia, and particularly in Ndola where the HIV prevalence among PWID is very high.

Reviewer #2: General comment:

Are there any prevention services available for PWID specifically in Zambia, either NSP or OAMT? The instrument asked about OAMT awareness but were there questions about uptake? Or where needles were obtained?

In comparing the results in the article with the IBBS report found online the values do not match (e.g. HIV prevalence in Lusaka is 21.9% in the article vs 21.3% in the report; the 95’s for Ndola in the article are 60.2%-100%-90.2% while in the report there are 61.9%-100%-83.7%… ). Could these discrepancies be clarified for readers who may look at the report, too?

Line 34: “progress of PWID”…is it progress of the PWID themselves or the epidemic response for and by them? It reads awkwardly as written.

Line 59: “Whereas the world’s general population has an HIV prevalence of 0.7%…”

It would be worth to specify if this refers to all ages, 15+ or any other age range. The same applies to all the values related to the general population in the article (e.g. Line 61).

Also, the value would need bounds, kindly add them, as well as all the rest of the values in the article.

Line 63: “…in which 19.6% of SSA PWID participate.”

The source from where the data come from specify that the people have participated recently.

Line 68: “… defined as HIV RNA of <1000 copies/mL during the most recent VL test”.

The source for this is: 2016 World Health Organization (WHO) Consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection. Kindly update it.

Lines 96-97: “…people living with HIV in Zambia was 59.2% (19).”

The correct citation for this seems to be "Ministry of Health, Zambia. Zambia Population-based HIV Impact Assessment (ZAMPHIA) 2016: Final Report. Lusaka, Ministry of Health. February 2019".

Line 101: “…assuming an HIV prevalence of 25%”.

Why assume a prevalence of 25% if the evidence shown on the introduction showed 15.2% globally and 11.2% in SSA?

Line 236: “…healthcare because they inject drugs…”

Please specify that they have being treated unfairly or denied healthcare by healthcare practitioners.

Line 253: “…injected for a median duration of 3 years (IQR: 6-10).”

Why the IQR do not have decimal numbers? Please consolidate with the rest of the article.

Line 266: “…with HIV, 70.8% (95% CI: 56.8, 85.1) were virally suppressed”. & Line 294 “…and 58.0% (95% CI: 27.8, 88.3) of…”

Why to use the cascade here if in the abstract and introduction the reference is the 95-95-95?

Lines 273-274: “…from peer educators and/or outreach workers (47.2%), internet (11.9%), television (8.5%), radio (2.9%), and/or friends (31.9%).” & Lines 288-289 “…workers (47.1%), internet (9.1%), television (35.9%), radio (56.6%), and/or friends (37.3%).”& Lines 303-304 “…workers (31.0%), the internet (5.7%), television (5.0%), radio (6.5%), and/or friends (13.8%).”

Why not adding IC 95% on these values?

Line 277: “…Number of Hepatitis B cases…”.

Could you kindly add that Hepatitis C cases too?

Line 284: “… because they did not feel at risk whereas 22.8% (7.2, 38.2) did…”

Please add that numbers within brackets correspond to 95% CI.

Line 332: “…forced sex, and lower awareness of non-injectable alternatives present unique challenges.”

Please specify where this sentence comes from. It hasn't been introduced through the article.

Line 343: “…(13.2%), where Livingstone is located (19).” & Line 344 “…women (5.9%) and men (1.8%) of the country-wide…” & Lines 354-355-356 “…slightly higher than women (5.9%) and men (1.8%) of Zambia’s general population of the same age group but lower than the all-age prevalence in the broader Lusaka province’s general population (14.4%) (19)” & Lines 373-374: “…Copperbelt province (11.9%) (19), where Ndola is located. It was also higher than women (12.0%) and men (3.1%) in…”

Specially interesting to include IC 95% here to see if those overlap with the results found.

Line 362: “…discovering they inject drugs, and almost 8.0%…”

Is 8 percentual points, may be confusing, perhaps helpful to clarify.

Line 368: “… avoidance of healthcare,…”

Please include that it is “high frequency of” avoidance of healthcare.

Line 376: “… almost double the prevalence…”.

Is most of the double of each of the other two cities.

Lines 456-457: “…was relatively low, awareness of the benefits of opioid agonist therapy was low…”

This was not mentioned before in the article, can be specified where this come from?

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Reviewer #1: No

Reviewer #2: Yes:  Keith Sabin

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 10.1371/journal.pone.0323919.r003 Author response to Decision Letter 1 Submission Version 1

6 Mar 2025

We recommend accessing our attached document entitled "Response to Reviewers" where all of our responses are laid out neatly, but we pasted that document here as well.

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

"https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf"

Author Response: Thank you. We have gone through and checked, and updated the formatting of the author list to denote groupings of those who contributed equally.

2. Please include a complete copy of PLOS’ questionnaire on inclusivity in global research in your revised manuscript. Our policy for research in this area aims to improve transparency in the reporting of research performed outside of researchers’ own country or community. The policy applies to researchers who have travelled to a different country to conduct research, research with Indigenous populations or their lands, and research on cultural artefacts. The questionnaire can also be requested at the journal’s discretion for any other submissions, even if these conditions are not met. Please find more information on the policy and a link to download a blank copy of the questionnaire here: https://journals.plos.org/plosone/s/best-practices-in-research-reporting. Please upload a completed version of your questionnaire as Supporting Information when you resubmit your manuscript.

Author Response: This file has been included with our resubmission. The file name is “Inclusivity-in-global-research-questionnaire”.

3. We note that the grant information you provided in the ‘Funding Information’ and ‘Financial Disclosure’ sections do not match.

When you resubmit, please ensure that you provide the correct grant numbers for the awards you received for your study in the ‘Funding Information’ section.

Author Response: The Award Number is: 1NU2GGH002056. We have ensured the reported numbers match in the financial disclosure statement and funding information section.

4. Thank you for stating the following financial disclosure:

[This activity was supported by the US President’s Emergency Plan for AIDS Relief (PEPFAR) (https://www.state.gov/pepfar/) through the US Centers for Disease Control and Prevention (CDC) under the terms of cooperative agreement “Supporting sustainable surveillance systems among key populations and support the Government of Zambia to improve HIV-related services for KPs” (Prime Award No. 1NU2GGH002056). The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the funding agencies. ].

Please state what role the funders took in the study. If the funders had no role, please state: ""The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.""

If this statement is not correct you must amend it as needed.

Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf.

Author Response: Thank you. We have amended the above financial statement to also include the requested information, which has been included in its totality in the cover letter as requested. You can see the revised statement here as well:

“This activity was funded by the US President’s Emergency Plan for AIDS Relief (PEPFAR) (https://www.state.gov/pepfar/) through the US Centers for Disease Control and Prevention (CDC) under the terms of cooperative agreement “Supporting sustainable surveillance systems among key populations and support the Government of Zambia to improve HIV-related services for KPs” (Prime Award No. 1NU2GGH002056). The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the funding agencies. CDC employees, whose specific roles are outlined in the author contributions section, provided technical assistance and input into the study design, data collection, data analysis, decision to publish, and preparation of the manuscript.”

5. We note that you have indicated that there are restrictions to data sharing for this study. For studies involving human research participant data or other sensitive data, we encourage authors to share de-identified or anonymized data. However, when data cannot be publicly shared for ethical reasons, we allow authors to make their data sets available upon request. For information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions. Before we proceed with your manuscript, please address the following prompts: a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially identifying or sensitive patient information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., a Research Ethics Committee or Institutional Review Board, etc.). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent. b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. Please see http://www.bmj.com/content/340/bmj.c181.long for guidelines on how to de-identify and prepare clinical data for publication. For a list of recommended repositories, please see https://journals.plos.org/plosone/s/recommended-repositories. You also have the option of uploading the data as Supporting Information files, but we would recommend depositing data directly to a data repository if possible. Please update your Data Availability statement in the submission form accordingly.

Author response: Thank you for this comment. The underlying data for this study are owned by the Zambian Ministry of Health and the National AIDS Council. Due to the sensitive nature of the data, which involve key populations that face legal and social risks, there are strict ethical and legal restrictions on data sharing. These restrictions are mandated by the institutional review board (IRB) requirements to protect participant privacy and confidentiality. For these reasons, the de-identified data can only be accessed upon request and after approval by the relevant Zambian health authorities. Researchers interested in accessing the data should contact:

Dr Kebby Chongwe Musokotwane

Director General

National HIV/AIDS/STI/TB Council

Plot 315, Independence Avenue

PO Box 38718

Lusaka, Zambia

Tel: +260-211-255044

KMusokotwane@nacsec.org.zm

Requests will be evaluated to ensure compliance with ethical standards and participant safety.

6. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Author Response: Thank you. We have ensured our reference list is complete and correct.

Additional Editor Comments:

1. Introduction (lines 82 - 84). The objective does not mention assessment or presentation of results around syphilis, HBV or HCV (STI and BBV), so consider noting these too.

Author Response: Thank you for noticing this. We have added these components into the relevant lines of the Introduction Section of the revised manuscript.

2. Introduction. The provision and availability of needle and syringe programmes (NSP) and opioid agonist maintenance therapy (OAMT) and treatment of stimulant dependence in Zambia should be briefly described.

Author Response: Thank you. The following basic information has been added into the 3rd paragraph of the introduction section:

“In addition, there are no PEPFAR or government-sponsored Opioid Agonist Maintenance Therapy (OAMT) or Needle and Syringe Programs (NSPs) available for the treatment of stimulant dependence in Zambia.”

We have also added information to the discussion section about some work that is happening to create policy, guidance, and institutional space for the hopeful enabling of methadone treatment in Zambia. This addition to the discussion section has been explained in more detail in our response to the editor’s later comment about NSP and OAMT in #11 below.

3. Methods (lines 92). Insert a short description about each study site for readers who may not be familiar with Zambia.

Author Response: The following descriptions have been added to the methods section:

“Livingstone is in Southwest Zambia on the border with Zimbabwe and has a high influx of visitors for Victoria Falls, but nonetheless has the smallest population of the three survey sites. Lusaka is in Central Zambia, is the nation’s capital, and has the largest population of the three sites. Ndola lies roughly 300 km to the north of Lusaka near the border with the Democratic Republic of the Congo.”

4. Findings. The findings section (notably descriptions) is a bit long in parts. Aim to focus on key findings, and reduce some descriptions of socio demographic characteristics, and refer to the table.

Author Response: Thank you, we agree. The language throughout the whole ‘Results’ section has been streamlined and shortened while some of the repetitive/less important descriptions have been reduced or omitted.

5. Findings. Table 1. Insert the % for all rows, where relevant (currently only done for some).

Author Response: We agree this helps with the standardization of the table. This has been done.

6. Findings. Unless I missed it, I did not see the description of the type of drugs injected. This is critical to assess risk, prevention and interventions.

Author Response: The most common type of drugs injected across the three sites has been added to Table 3 and the corresponding paragraph in the findings. There will be another manuscript published from another partner research group that goes into more detail about injection drug practices, prevention, and interventions in this PWID population, which is why we originally didn’t include it here. However, we agree that this brief background will help contextualize the 95-95-95 progress we are reporting on. Thank you for this suggestion.

7. Table 3. Median duration of injecting. Check the median and p25 and p75 - I would expect the median to lie between these, but does not seem to be the case (e.g., Ndola median is 3.0 years, but IQR is 6 - 10 year).

Author Response: Thank you so much for noticing this, not sure how it slipped by after so many reviews on our end. These medians and their p25 and p75’s have been recalculated and have now been fixed in Table 3. These numbers have been corrected within paragraphs where median duration of injecting was reported or referenced as well.

8. Insert n for anti-HCV results and HCV PCR for sample in table and findings description.

Author Response: Thank you for your comment. With such small sample sizes, it was the team’s policy to put an asterisk in place of n’s that were 5 or less in order to protect this vulnerable population from being identified through data triangulation. In any tables in which an asterisk is shown, the asterisk is described as such in the table’s footnote. All of the local authors and advisors from the vulnerable groups themselves agreed with this decision. It was a deliberate choice so they could not be identified by an employer, family member, etc. since stigma and bias is so common with this group.

9. Findings around awareness of OAMT - this would only apply to people with opioid dependence, but it is not clear what drugs people injected. Also, Table 3 notes " aware of any drug treatment programs" - this is too broad to reflect insights into OAMT. So if questions on OAMT were asked, please include. If not, this could be noted in the limitations.

Author Response: Thank you, this is great insight. In response to this and your previous comment about not knowing which types of drugs people injected, we included in Table 3 the most common types of drugs injected across the three sites, so it is our hope this provides some helpful context. In addition, an asterisk is included in the ‘Awareness of any drug treatment programs’ variable of Table 3 corresponding to a footnote that provides further details by stating that the variable includes outpatient, inpatient, residential, detox, and methadone maintenance drug treatment programs. Unfortunately, the original survey question written years ago didn’t tease out awareness based on type of program into any more detail than this, so this has been noted in the Limitations section too as you suggested:

“Our variable on awareness of drug treatment programs (including outpatient, inpatient, residential, detox, and methadone maintenance therapy) is of limited value since OAMT and NSPs are currently not available in Zambia, however the low awareness observed indicates work must be done to increase awareness on the benefits of these programs if they are to be maximally successful if and when they are approved in Zambia.”

10. Findings. Why no findings of needle reuse/ sharing? This is the most important risk factor for PWID? (Unless I missed it). This is key to include, as it is a UNAIDS GAM indicator. Please include these variables.

Author Response: An indicator regarding frequency of needle reuse in the last 6 months has been included in Table 3 and the corresponding paragraph. We definitely agree with your statement but originally didn’t include this variable in the manuscript because survey designers wrote this question subjectively. The original survey question had response categories of ‘Never’, ‘Rarely’, ‘Half of the time’, ‘Most of the time’, ‘Always’, and ‘Don’t know/No answer’. For the purposes of the paper, these categories have been recoded into ‘Never’, ‘At least once’, and ‘No answer’ to make it as objective and accurate as possible given the constraints in how this question was originally constructed.

11. Discussion. Among PWID, the primary HIV prevention interventions are NSP and OAMT, these should be foregrounded. These interventions are more important for PWID than PrEP, yet there is much emphasis on PrEP. Similarly, the implications for policy and practice, NSP and OAMT need to be much higher priorities than PrEP, but the framing does not align with emphasis on the issues that are particular to PWID. There is mention of MAT clinics, but what about NSP? This is critical, as many African countries are resistant to NSP, but without NSP HIV prevention interventions for PWID will fail to be effective.

Author Response: We agree NSPs and OAMT are very important for PWID. Unfortunately, as discussed above in our response to your other comment regarding the introduction section, they are currently not available in Zambia, whereas PrEP is. However, there is work going on regarding getting OAMT approved so we have added some detail about this into our “Implications for Program and Policy” subsection of the Discussion. Please see the information that has been added to the discussion section below:

“…Preventive resources like PrEP can be efficiently offered in these facilities as well (59), along with OAMT (60)) and NSPs. Results from the 2021 BBS have already propelled the establishment of a PWID task force with representation from government and non-governmental agencies that is working to establish MAT clinics while the police and Home Affairs Ministry offer basic rehabilitati

Submitted filename: Response to Reviewers.docx

 10.1371/journal.pone.0323919.r004 Decision Letter 1 Jahun Ibrahim Academic Editor 2025 Ibrahim Jahun This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication. Submission Version 1

17 Apr 2025

Local data for local programming: Results from an HIV biobehavioral survey among people who inject drugs in Livingstone, Lusaka, and Ndola, Zambia, 2021

PONE-D-24-29546R1

Dear Dr. Woytowich,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Reviewers' comments:

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Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #3: (No Response)

Reviewer #4: All comments have been addressed

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Reviewer #3: Yes

Reviewer #4: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #3: Yes

Reviewer #4: Yes

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Reviewer #3: No

Reviewer #4: Yes

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Reviewer #3: Yes

Reviewer #4: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #3: The manuscript presents a cross-sectional survey of people who inject drugs (PWIDs), aged over 16 years, on HIV indicators, syphilis, HBV and HCV and associated risk behaviours in three cities in Zambia: Livingstone, Lusaka and Ndola. The median age was 23 in Livingstone, 24 in Lusaka and 28 in Ndola. There was low female representation among PWIDs with Ndola having the highest at 30% and Lusaka lowest at 2%. The research shows significant differences in HIV prevalence of PWIDS across the three sites with the highest having a prevalence of 21.9% (Ndola) and the lowest 7.3% (Lusaka). Risk perception was low among all the three sites. Progress towards the UNAIDS 95/95/95 targets was poor among the three sites with Lusaka being the worst performing. Sypilis prevalence was highest in Ndola at 11.1% and lowest in Livingstone at 3%. Prevalence of both hepatitis B and C was low.

The authors have highlighted the study limitations that include social desirability and recall bias.

Overall, the manuscript is well written, with the various sections bringing out the relevant information. The presentation of the results by site/city has revealed important similarities and differences that could inform PWID program implementation.

The conclusions reflect the data that is presented.

The authors have not made all the data available due to ethical and legal reasons. They have described where the data can be accessed.

Reviewer #4: This recommendation I have made is based on authors response to the initial reviewers' comments. Having read the revised (clean) manuscript before reading the the reviewers comments, and authors response and tracked version, I was able to appreciate that the manuscript was clear and logical. Nothing stood out as a particular concern to me. Being from the country where this work was done, I am also able to relate with the context in which this survey was done and attest that this has been an under studied key population. Therefore, the data presented is highly relevant and highlights an important challenge for Zambia to achieving the 95-95-95 control of HIV by 2030. This challenge is certainly not unique to Zambia. Even though the manuscript highlights marked differences in the cities that were considered, the recommendations are widely applicable. The messages and recommendations contained in this manuscript may be applicable to other settings in the region and globally as it relates to PWID and HIV.

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Reviewer #3: No

Reviewer #4: No

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 10.1371/journal.pone.0323919.r005 Acceptance letter Jahun Ibrahim Academic Editor 2025 Ibrahim Jahun This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

PONE-D-24-29546R1

PLOS ONE

Dear Dr. Woytowich,

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Academic Editor

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