Five successive waves of SARS-CoV-2 infection in the Central African Republic: a prospective observational study from 2020-2022

Introduction: the National Laboratory of Clinical Biology and Public Health (NLBPH) in Bangui in the Central African Republic (CAR) carries out the vast majority of molecular screening tests for SARS-CoV-2 infection nationwide. This study aimed to show the contribution of molecular diagnosis and genomic surveillance in monitoring the evolution of longitudinal variations of the SARS-CoV-2 infection epidemic in CAR between 2020 and the end of 2022.

Methods: this is an observational study on the variations in the prevalence of detection of SARS-CoV-2 by RT-PCR at the NLCBPH from nasopharyngeal samples taken prospectively over a period of 3 years since the beginning of the COVID-19 epidemic. A subgroup of SARS-CoV-2 positive samples was selected for molecular sequencing performed by Illumina® and MinIon® at the National Institute for Biomedical Research in Kinshasa, Democratic Republic of the Congo.

Results: from March 2020 to December 31^th, 2022, 88,442 RT-PCR tests were carried out (4/5 of the country) and detected 9,156 cases of SARS-CoV-2 infection in 5 successive waves. The average age of the patients was 39.8 years (extremes ranging from to 92 years). Age(P=0.001), sex(P=0.001) and symptom presentation(P=0.001) were significantly associated with RT-PCR test positivity. Among the different variants identified during successive waves, the Omicron variant predominated during the last two waves.

Conclusion: this prospective study over a period of 3 years, marked by 5 successive waves, made it possible to report that age, sex and the presence of clinical symptoms are associated with RT-PCR positivity. Among the different variants identified during successive waves, the Omicron variant predominated during the last two waves.