Cumulative seroprevalence of SARS-CoV-2 antibodies among blood donors in Burkina Faso, April 2022.

Introduction: In Sub-Saharan Africa, the true extent of the COVID-19 pandemic is not known due to the low number of tests performed and the large proportion of asymptomatic cases in the populations. This was a seroprevalence study of SARS-CoV-2 antibodies in blood donors to assess the extent of virus circulation in Burkina Faso.

Methodology: It was a cross-sectional study that included unpaid blood donors between March and April 2022. A rapid diagnostic test was used to screen SARS-CoV-2 antibodies in donors' plasma. Adjustment was made based on the performance of the test evaluated in a national quality control.

Results: A total of 3,084 blood donors were recruited, of whom 58.7% were male and 59.8% were from urban areas. The mean age was 22.9 ± 5.8 years, with donors aged 20 to 29 years accounting for 64.2%. The adjusted seroprevalence was 87.2%; 95% CI (86.4- 87.9). There was no difference in SARS-CoV-2 seropositivity between men and women, and between urban and rural areas. Donors aged 30-39 years had 0.5-fold lower odds of having SARS-CoV-2 antibodies than those under 20. Similarly, compared to Bobo-Dioulasso, blood donors from the Dédougou, Fada N'Gourma, and Koudougou centres had 0.5, 0.2, and 0.5 times lower odds of having SARS-CoV-2 antibodies, respectively.

Conclusions: The study indicates a high population exposure to SARS-CoV-2, in contrast with the official reports from the national surveillance system. It underscores the need to strengthen surveillance and public health interventions both in urban and rural areas.