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 increased more than seven times in patients aged ≥ 70 years old (aRR = 7.12, p = 0.001), more than six times in married (aRR = 6.60, p = 0.02), more than seven times in those having completed secondary studies (aRR = 7.85, p = 0.02), HIV-positive patients (aRR = 7.64, p < 0.0001) and asthmatic patients (aRR = 7.60, p = 0.003), and more than nine times in those seeking health care regularly (aRR = 9.24, p = 0.001). In contrast, the risk of SARS-CoV-2 infection was reduced by 86% in patients attending Bonassama hospital (aRR = 0.14, p = 0.04), by 93% in patients of blood group B (aRR = 0.07, p = 0.04), and by 95% in COVID-19 vaccinated participants (aRR = 0.05, p = 0.005). There is need for ongoing surveillance of SARS-CoV-2 in Cameroon, given the position and importance of Douala.