Since early 2020, the COVID-19 pandemic has affected the world in an unprecedented manner. The impact of this disease on people living with HIV (PLWH) is still being explored. Reports from various studies show a lower incidence of COVID-19 among PLWH (0%–3.7%) compared to the general population (4%–7.4%) (1–4). It thus may appear that HIV patients with normal CD4 T-cell counts, suppressed viral loads, and receiving regular combined antiretroviral therapy (cART) do not present with a severe clinical course of COVID-19 and may not be at an increased risk of developing SARS-CoV-2 infection (4). However, the high asymptomatic nature of COVID-19 coupled with differential testing has been reported to be confounders in the assessment of SARS-CoV-2 incidence among PLWH compared to the general population. According to an analysis conducted in San Francisco, matching the San Francisco Department of Public Health COVID-19 testing and case database and the San Francisco Department of Public Health HIV Surveillance case registry, PLWH were found to be more susceptible to COVID-19 infection compared to the general population (5). In South Africa, a setting of relatively high HIV endemicity, it was found that, due to an HIV-related immune response, PLWH may experience more severe disease from COVID-19 (6).

PCR-based testing is still a major challenge in most parts of Africa and might be the reason why PCR-based SARS-CoV-2 prevalence data is scarce. Besides, there is a high degree of variability in the incidence of COVID-19 in African communities compared to those of other continents. This warrants seroprevalence studies to determine actual exposure rates within the general population and representative subsets, such as PLWA. Despite the challenge of conducting clinical research during an ongoing pandemic, a few systematic seroprevalence studies comparing SARS-CoV-2 infection rates by HIV status have been conducted in Italy, the USA (7, 8), and some parts of Africa (9, 10), suggesting fewer SARS-CoV-2 infections among PLWH compared to the general population. Like the rest of Africa, Cameroon is affected by COVID-19 and HIV pandemics counting over 504,472 PLWH with a prevalence of 2.9% in adults aged 15–49 years (11). The country registered its first confirmed COVID-19 case on 4 March 2020. As of 10 March 2023, 1,965 deaths and 124,392 COVID-19 cases were recorded in Cameroon (12). In a recent study conducted in Cameroon, SARS-CoV-2 antibodies were found in PLWH as early as 2019, which may attest to the presence of the disease before the pandemic was declared (13). Since various comorbidities increase the risk of SARS-CoV-2 infection, it is crucial to assess the potential contribution of HIV to the risk of acquiring this new pathogen. With the ongoing debate on whether PLWH might be at an increased risk of severe COVID-19 (13), our study, which used serological testing, will contribute to the emerging data measuring the COVID-19 disease burden in PLWH. Understanding seroprevalence and the rate of actual cases is necessary to better manage epidemics, hospitalizations, and deaths in a well-defined population, helping to make some inferences about a larger population. Our study aimed to compare the anti-SAR-CoV-2 IgG seroprevalence among people living with and without HIV receiving healthcare in two non-governmental health facilities in Douala, Cameroon.

In this study, we described the seroprevalence of SARS-CoV-2 IgG among people with and without HIV receiving healthcare in two non-governmental health facilities in Douala, Cameroon. The general SARS-CoV-2 IgG seroprevalence in this study was estimated at 42.31% and was relatively higher among PLWH, at 44.68% (21/47), compared to HIV-negative patients, at 38.71%, though no statistical significance was observed. A previous community-based study in Cameroon reported a 29.2% seroprevalence of anti-SARSCoV-2 IgG antibodies (16). It should be noted that this previous investigation occurred from 14 October to 26 November 2020, a year earlier in the pandemic when compared to the present study. Other studies in different parts of the world have documented evidence of previous exposure to SARS-CoV-2. In Iran, for example, an IgG seroprevalence of 39.0% was found in a study conducted at the beginning of the pandemic, in April and May 2020 (17).

We note some variability in reported seroprevalence results in Africa ranging from 2.6% in Sierra Leone (18) to 45.1% in Nigeria (19). In our study population, participants did not report any previous SARS-CoV-2 infection, no one had received a COVID-19 vaccine, and all were asymptomatic. It is thus possible that the IgG seropositivity observed within this population indicates the participants’ natural immune response to SARS-CoV-2 infection, irrespective of their HIV status. Several reasons, such as the nature of the virus, the host’s characteristics, and various aspects of the African environment, were previously evoked for the unexpectedly low burden of COVID-19 reported in Africa since the beginning of the pandemic (20). Taking only the pre-vaccine period into account, levels of SARS-CoV-2 IgG seroprevalence around the world were also found to vary. In a study conducted in the United States, a seroprevalence of 20.2% was found during the period of July 2020–May 2021 (21). In Canada, also during the pre-vaccine period, a prevalence of 4.6% was found (22), while in Brazil around the same period, a seroprevalence of 25.4% was found (23). For the eastern region of the world, a study conducted in Kuwait found a seroprevalence of 24.8% (24). In more general terms, a meta-analysis was conducted on articles from 88 countries, namely, original articles published from December 2019 to December 2021, and it was concluded that the pooled estimate of seroprevalence SARS-CoV-2 was 15% in Eastern Mediterranean countries, 6% in Africa, 8% in the Americas, 5% in Europe, and 3% in the Western Pacific (25). It is challenging to discuss comparisons with such a variety of results.

Underreporting has also been claimed to be responsible for the lower COVID-19 disease burden in Africa compared to other parts of the world (26–28). Our study corroborates this claim as 42% of our participants who showed evidence of previous infection were never reported as confirmed cases of COVID-19. In addition, the asymptomatic nature of the participants indicates a mild form of COVID-19 occurrence within the population, as found in several studies around the world (29–32). Mindful of the unimmunized nature of the study population, this asymptomatic nature could be the result of a pre-existing cross-reactive immunity conferred by the exposure of the Cameroonian population to other forms of coronaviruses prior to the onset of the pandemic, as suggested by Aissatou et al. (13). Furthermore, relative higher seroprevalence (although not statistically significant) was recorded among PLWH compared to the HIV-negative group. Meanwhile, HIV-positive patients were on a Tenofovir antiretroviral regimen, which could mean that PLWH with adequate adherence to ART (antiretroviral treatment) are not at a lower risk of contracting COVID-19 compared to the general population. Similar results were found in a documented case series of 33 patients in German HIV centers where darunavir and Tenofovir ARV boasted regimens were shown to increase the risk of SARS-CoV-2 infection in HIV patients (33).

As shown in Table 2, when adjusted for age, sex, and religion, the odds of having suffered from a previous infection were significantly associated with marriage. In a previous seroprevalence study conducted in Cameroon by Fai et al., age, gender, and comorbidities were significantly associated with SARS-CoV-2 IgG antibodies, contrary to our findings (34). These findings may be attributed to the difference in the study populations. In addition, the Fai study included hospitalized patients admitted with severe COVID-19 disease, which may explain the association between age and comorbidities.

In our study, among the PLWH, suppressed viral load, ART regimen, and duration of HIV infection were not significantly associated with IgG seropositivity. Our findings are similar to those obtained in a study conducted in Spain, where no association was found between suppressed viral load and SARS-CoV-2 seropositivity among PLWH (8). The possible protective benefits of Tenofovir on SARS-CoV-2 infection are likely due to its immunomodulatory effects (35). Other studies refuted the assumption that PLWH under a Tenofovir regimen and suppressed viral load are at a lower risk of COVID-19 morbidity and mortality. Nomah et al., found that PLWH receiving tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) were not at a higher risk of SARS-CoV-2 infection (36). At the same time, another study failed to find excess morbidity or mortality among PLWH, especially those with viral load suppression on ART (10).

Our findings support the lack of association between HIV status and susceptibility to SARS-CoV-2 infection. Furthermore, as shown in previous investigations, the ARV regimen, suppressed viral load, and Tenofovir boasted ARV regimen might not affect the body's immune response after exposure to SARS-CoV-2 among PLWH and HIV-negative individuals. Thus, if HIV is well treated, the susceptibility to COVID-19 would be similar to those of the general population.

Future studies with larger samples, including multiple study sites and subgroup analyses based on the immunological status of HIV-positive patients, will provide further evidence.