SARS-CoV-2 Detection on One Laboratory of COVID-19 Monitoring in Douala Cameroon and Associated Risk Factors of Viremia

Abstract

Background: As soon as the COVID-19 epidemic outbreak in Cameroon, the Douala General Hospital (DGH) was performed to monitor the evolution of this infection with RT-PCR analysis. The aim of this study was to identify risk factors associated with viremia of samples analyzed by molecular biology at the Douala General Hospital laboratory, in the context of a major SARS-CoV-2 epidemic. Methodology: A cross-sectional study was carried out in the Molecular Biology Unit of the Clinical Biology Laboratory at the Douala General Hospital. All nasopharyngeal samples received for diagnosis or screening by PCR were analyzed. Samples were obtained from approved sampling centers in Douala (11 Health Districts) and from many departments at the DGH. Real-time RT-PCR targeting the N and Orf genes using the “Daan Gene Co., Ltd., Sun Yat-sen University” kit was performed according to the manufacturer’s recommendations. The results were interpreted according to the appearance of the gene signal, with a detectability threshold of 37 cycles. A sample was declared positive if both genes had a Ct Results: From 28 December 2020 to 31 December 2022, 45,243 non-repeated samples were received and analyzed. The sex ratio was 1.52. The average age was 40 years (0 - 104), and the most represented age group was 30 - 45 years (39.4%). Of these samples, 47.2% (21,351/45,243) and 46.6% (21,065/45,243) came from travelers and contact cases, respectively. Only 2.9% (1304/45,243) were symptomatic. Molecular analysis revealed an overall positivity rate of 8.4% (3808/45,243). A proportion of 31.1% (1185/3,808) was classified as highly positive with CT values Conclusion: RT-PCR was used to establish an adequate biological diagnosis of SARS-CoV-2 infection in a highly turbulent health context. In the context of a major epidemic, this technique could be necessary for the follow-up of this infection, with a clear diagnosis of low viral load (CT > 30) with seasonal peaks in positivity.