Severe acute respiratory syndrome coronavirus-2 (SARS-COV-2), is the etiological agent for the COVID-19 disease which is currently a pandemic. This virus continues to spread globally with an average infection rate of 2.5, leaving over 20 million people infected with more than 700,000 associated deaths reported [1]. Although the infection could be asymptomatic, symptomatic signs may be mild, moderate severe or critical [2, 3]. Earlier reports showed a 26.4% risk of dying among individuals above 60 years and 4.1% of all deaths occurring in those below the age of 45 years [4]. Cases of COVID-19 in Africa has not been so alarming compared to the rest of the world. As of November 04, 2020, there were 1,814,642 reported cases in Africa which has resulted in over 40,000 deaths [5] compared to 9,383,979 and 10,866,134 cases resulting in 232,635 and 277,125 deaths in the United States (US) and Europe, respectively [5, 6]. Ghana confirmed her first two cases of COVID-19 on 12^th March, 2020 [7] and the case counts have risen to 48,643 with 320 deaths as of 4^th November, 2020 [8].

Various interventions including closure of borders, schools, mandatory wearing of masks and targeted lockdown have been introduced by the Government of Ghana in order to limit surges and the spread of infections. Although situational reports are usually provided by the Ministry of Health, detailed epidemiological data on cases are limited. To date, we do not have information on age and gender specific association with infection and the growth rate of the virus. The dynamism of viral load in different age groups, symptomatic and asymptomatic populations is also not well described. Measurement of viral load is indicative of active viral infection and replication. Higher viral load is associated with the onset of disease and it is a parameter for monitoring disease progression, treatment response, and relapse [9]. Zou et al., (2020) reported that among COVID-19 patients, both symptomatic and asymptomatic patients have similar viral load measurements [10]. The dynamics of the viral load distribution of the disease is however not fully understood in African populations. Correlations have been drawn between Middle East Respiratory Syndrome Coronavirus (MERS-CoV) disease distribution and gender with reports demonstrating higher disease incidence and severity among males [11]. This pattern is however yet to be explored in African populations.

The World Health Organization (WHO) has advised that decisions about this virus should be informed by evidence of data and science. It is therefore important that detailed epidemiological profile of those infected by the virus be provided in order to guide various interventions that could be implemented on the African continent. This study therefore aimed to describe the socio-demographic features, pattern or rates of virus infection through the period of this pandemic and viral load dynamism in subpopulations of SARS-CoV-2 infected individuals.

Human coronaviruses have contributed significantly to the burden of respiratory tract infections globally. Prior to the SARS-CoV and MERS-CoV outbreaks in 2003 and 2012, respectively, coronaviruses were thought to cause mild, self-limiting respiratory infections in humans [13, 14]. However, occurrence of these outbreaks and subsequent emergence of the current COVID-19 pandemic have changed the narrative. This study showed the cumulative detection of 9,549 (13.2% of tested specimens) SARS-CoV-2 in the study areas examined. The observed positivity rate was higher than the current national prevalence of 9.7% and reflects active transmission phase of the virus in these regions. Sustained person to person transmission was ongoing with localized outbreaks and possible surges in hotspots.

Although, majority of the sampled individuals were females (51.9%), a higher proportion of those who tested positive were males. This is comparable to other studies with high proportions of SARS-CoV-2 infection in males [15–19]. This male preponderance to infection has been explained by some studies that mast cells in females are able to trigger a more active immune response, which may help them fight infectious diseases better than males [18]. Furthermore, other genetic components such as the X chromosomes and hormones, typically estrogens, both predominantly found in females have been linked to provide some significant level of protection against SARS-CoVs [18, 20]. Interestingly, this study showed that older individuals (>60 years old) were less likely to be infected with COVID-19 than the younger groups (Table 2). One reason for this observation could be that the young groups are actively working and outdoor engagements were rampant, with little adherence to safety protocols, resulting in increased cases. This observation agrees with data from Brazil [21] and suggests that younger persons could be major drivers of SARS-CoV-2 infections. Notwithstanding, all age groups are at risk of contracting COVID-19, and in terms of disease severity, older individuals are at a greater risk due to physiological changes that come with ageing, compromised immune system and potential underlying health conditions [22].

Our study also measured the viral loads of subjects whose samples were analyzed at KCCR in Kumasi. The viral load profile is important for guiding antiviral treatment and could explain the pattern of recovery and transmission of infections. Unlike other studies which showed children had higher loads of the virus than adults [23], our study identified a higher load of the virus in elderly persons compared to younger persons. The finding is consistent with previous reports of SARS-CoV which suggest older age was an independent factor associated with higher viral load and that these could contribute to impairment of the innate and adaptive immune responses and increase the risk of death [24]. This phenomenon could explain why older persons are dying more in Africa than younger age groups.

An evaluation of the viral loads between symptomatic and asymptomatic subjects was also analyzed. Symptomatic subjects had higher loads of the virus than asymptomatic subjects. For symptomatic subjects, those with severe symptoms had higher loads than those with mild symptoms. There are mixed reports of variation in viral loads of symptomatic and asymptomatic populations. Lavezzo et al., reported that there was no difference in viral loads for symptomatic and asymptomatic subjects compared in the Italian city of Vo [25]. Our findings corroborate a report by Liu et al., which observed higher mean viral load in subjects with severe symptoms compared to mild clinical presentations [26].

In order to slow down the rapid spread of the virus, several interventions were adopted and implemented by the Government of Ghana. Of note was the imposition of partial lockdown in some major cities in the country for 3 consecutive weeks. We observed the rate of positivity of the virus was very low (0.85%) during the lockdown period compared to the period before (6.1%) and after (23.4%) the lockdown intervention. Although the difference in virus detection was significant, it was unclear whether this was as a result of the lock-down intervention. The low prevalence observed during the lockdown period could be as a result of an enhanced contact tracing of large populations most of whom were asymptomatic. Most of the testing performed before and after the lock-down period targeted symptomatic individuals and thus more likely to yield positive results. Some authors have reported imposition of lockdowns as leading to significant reduction in infections [27] but this evaluation would require an adequate and consistent sampling and testing approach.

In COVID-19 patients, the main clinical manifestation is fever and cough often characterized by lymphocytopenia and ground-glass opacity changes on chest computed tomography [28]. However, due to the evolving nature of COVID-19, information regarding symptoms is also evolving. Apart from fever, cough, sore throat and other flu-like symptoms, this study identified anosmia (loss of smell) as the strongest predictor of SARS-CoV-2 infection, and this evidence is consistent with other studies reported elsewhere [29–31]. One possible reason could be because of the expression of SARS-CoV-2 receptors (ACE₂ and TMPRSS2) in the nasal respiratory epithelium and olfactory sensory epithelium which enables the virus to cause injury to the cells. More recently, an association between COVID-19 and altered olfactory function has been reported in South Korea, Iran, Italy, France, UK and the United States [32–34].

We identified 3 SARS-CoV-2 related deaths during the study period. This could be underestimated and may not reflect the number of deaths in the study areas due to limited data availability. We noted that most of the samples were collected from patients who had passed on and for which the hospital management wanted to rule out COVID-19 associated deaths. Deaths which occurred after laboratory samples tested positive were not reported back to our Centre. A large number of deaths from COVID-19 pandemic have occurred in the United States, China, the United Kingdom, Italy, Iran and Spain, with relatively fewer deaths recorded in Africa [35]. The relatively lower death toll of COVID-19 in Africa may be due to differences in genetic or climatic factors, or perhaps the impact is yet to be felt [35]. Studies have shown that comorbidities have the tendency of increasing individual’s susceptibility to COVID-19, especially among the elderly [36]. Chronic non-communicable diseases have been noted to have significant influence on COVID-19 prognosis, although these conditions account for a relatively lighter burden in Africa compared to developed countries [35]. Many of the poorer outcomes, including increased mortality due to COVID-19 have been related to cardiovascular comorbid conditions [37–39]. However, a large multicentre study conducted in Italy contrasts this finding and reports on factors such as age, renal impairment and high C-reactive protein levels to have strong predictive roles for mortality [40]. Another important aspect to look out for especially in sub-Sahara Africa is the occurrence of COVID-19 and malaria incidence. Gennaro et al., reported that malaria and COVID-19 present similar aspects and this seems to have a strong potential for mutual influence [41]. Healthcare professionals through the ministries of health and national malaria control programs are advised to ensure that malaria control efforts are not disrupted while dealing with the COVID-19 response [42, 43].

One limitation of this study was our inability to test other known respiratory viruses among the subjects. This is particularly important because negative results for SARS-CoV-2 does not necessarily rule out the possibility of other respiratory pathogens. Future studies could explore the role of other clinically relevant viruses among subjects with respiratory tract infections.

We have demonstrated high cumulated prevalence of COVID-19 in northern, middle and part of the southern belt of Ghana is high, with males and younger individuals at greater risks of contracting the disease. Clinicians should be mindful of the symptom of anosmia especially in outpatients in order to minimize delays in the diagnosis of COVID-19.