Post-Omicron SARS-CoV-2 serostatus in Sierra Leone: A cross-sectional study in a maternity hospital setting in Freetown, November/December 2022

• Main Authors: Sebastian Ruf (Author), Doris Harding (Author), Samuel Sorie (Author), Foday Musa Janneh (Author), Stefanie Theuring (Author)
• Format: Book
• Published: Elsevier, 2024-09-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 1876-0341; 10.1016/j.jiph.2024.102518
• Keywords: COVID-19; SARS-CoV-2; Sierra Leone; Sub-Saharan Africa; Antibodies; Seroprevalence; Infectious and parasitic diseases; RC109-216; Public aspects of medicine; RA1-1270
• Source: Journal of Infection and Public Health, Vol 17, Iss 9, Pp 102518- (2024)

Background: Spread of SARS-CoV-2 in Sub-Saharan African countries has been poorly investigated, especially in the later pandemic stages. We aimed to assess the post-Omicron situation in Sierra Leone in November/December 2022 considering SARS-CoV-2 serostatus, vaccinations, and behavioral factors. Methods: In a cross-sectional study conducted in a maternity hospital in Freetown, Sierra Leone, both patients and staff provided dried blood spot samples for analysis of anti-S and anti-N IgG prevalence using Anti-SARS-CoV-2-ELISA. Additionally, we collected sociodemographic and infection-related information through questionnaires. Outcome parameters included seropositivity, infection-related seroprevalence, and self-reported vaccination status. We used logistic regression to identify associations with prior infection and with vaccination status. Results: Out of 791 participants (389 patients, 402 staff), 670 (84.7 %) displayed a positive SARS-CoV-2 serostatus resulting from either infection or vaccination. Among a sub-sample of 514 participants within which determination of prior natural infection was possible, 441individuals (85.8 %) were affected. Prior infection was associated with female sex and tertiary education level. Overall, 60.3 % reported having been vaccinated. Staff as opposed to patients, and individuals with higher socioeconomic status were more likely to report vaccination. Individuals who assessed their risk of COVID-19 as either higher or lower compared to a medium-level risk were more likely to have contracted the virus and less likely to have received vaccination. Conclusion: Our findings suggest that since the Omicron wave in 2022, the Sierra Leonean population has almost universally been exposed to SARS-CoV-2. While this is encouraging in the light of relatively low excess mortality in the country, future investigations on the long-term effect of high viral exposure on epidemic resilience and public health impact will be crucial.