Previous or current infection with SARS-CoV-2 virus and its impact on maternal and neonatal health outcomes in Benin: a sero-epidemiological study in pregnant women

Background: SARS-CoV-2 (COVID-19) has emerged as a significant global public health challenge, revealing critical vulnerabilities within health systems worldwide. While extensive data on COVID-19 is available from high-income countries, information remains scarce in lower-income regions, particularly regarding its impact on pregnant women. This study aims to evaluate the burden of COVID-19 among pregnant women and its effects on maternal and birth outcomes during the third wave in Benin. Methods: A cross-sectional, hospital-based survey was conducted from May 19 to September 19, 2022, at the Lagune Mother and Child Teaching Hospital. A standardized questionnaire was administered, and nasal swabs along with serological analysis were performed on 437 pregnant women. Multivariate logistic regression was used to assess risk factors and evaluate the impact of previous or current COVID-19 exposure on maternal and birth adverse outcomes. Results: SARS-CoV-2 was detected in less than 1% of pregnant women through PCR testing of nasal swab samples. Among the study population, 14.4% of women were vaccinated against COVID-19. A total of 81.1% of women tested positive for antibodies, suggesting prior exposure or infection to SARS-CoV-2 or vaccination. Notably, 78.6% of unvaccinated women had detectable antibodies, which serves as a more accurate proxy for infection prevalence. No significant association was found between prior COVID-19 exposure and adverse maternal and birth outcomes (aOR: 0.48, 95% CI 0.15–1.51). Conclusions: Although PCR testing revealed a low incidence of active SARS-CoV-2 infection, the high prevalence of IgG antibodies among pregnant women suggests widespread prior exposure or infection. Vaccination was identified as a strong predictor of detectable IgG antibodies. Notably, despite the presence of antibodies, no significant association was found between prior COVID-19 exposure and adverse maternal or birth outcomes. These findings highlight the need for further research to explore the potential long-term effects of COVID-19 infection on pregnancy outcomes and to better understand the relationship between antibody presence and maternal and fetal health.