Impact of a Mass Campaign on the Evolution of the Fourth Wave of the Covid-19 Pandemic in the Central African Republic

Objective: In the context of increasing cases despite vaccination campaigns, a survey was conducted in the Bangui population from January 17 to 26, 2022, to evaluate the strains of Severe Acute Respiratory Infection Coronavirus 2 (SARS-Cov-2) circulating in a healthy population. Materials and methods: This study was conducted by taking nasopharyngeal samples from randomly selected volunteers. Antigen detection was performed systematically, and RT-PCR was done on the positive samples. Results and discussion: We collected 2,554 samples. Thirty were found RT-PCR positive (1.2%) and sent for viral genome sequencing. Twenty-eight SARS-Cov-2 strains belonged to the Omicron type, and only 2 to the Delta type. Conclusion: Thus, infections were uncommon in the tested population, but the presence of Omicron and Delta types raises concerns that vaccination may not be effective in fighting the virus, and newly designed vaccines should be implemented to better protect the population at risk of infection and reinfection by these variants.