Epidemiological Situation of SARS-CoV-2 Infection in Douala, The Most Populated and Highly Heterogeneous Town of Cameroon: A Post-Vaccination Update

This study aimed at providing an update of SARS–CoV–2 epidemiology in Douala, the most populated and highly heterogeneous town of Cameroon. A hospital–based cross sectional study was conducted from January to September 2022. A questionnaire was used to collect sociodemographic, anthropometric, and clinical data. Retrotranscriptase quantitative polymerase chain reaction was used to detect SARS–CoV–2 in nasopharyngeal samples. Of the 2354 individuals approached, 420 were included. The mean age of patients was 42.3 ± 14.4 years (range 21 – 82). The prevalence of SARS–CoV–2 infection was 8.1%. The risk of infection with SARS–CoV–2 was seven times increased in patients aged ≥ 70 years old (aRR = 7.12, p = 0.001), and more than six times in married (aRR = 6.60, p = 0.02), those having completed secondary studies (aRR = 7.85, p = 0.02), HIV-positive patients (aRR = 7.64, p < 0.0001), asthmatic patients (aRR = 7.60, p = 0.003), and those regularly seeking health care (aRR = 9.24, p = 0.001). In contrast, the risk of infection was reduced by 86% in patients attending Bonassama hospital (aRR = 0.07, p = 0.04), by 93% in patients of blood group B (aRR = 0.14, p = 0.04), and by 95% in COVID–19 vaccinated participants (aRR = 0.05, p = 0.005). There is a need for ongoing surveillance of SARS–CoV–2 in Cameroon, given the position and importance of Douala.