High exposure of pregnant women to SARS-CoV-2 during COVID-19 waves in Senegal.

BACKGROUND

The COVID-19 pandemic raised concerns about SARS-CoV-2 infection in pregnant women, especially regarding pregnancy outcomes and maternal-child health. Despite the limited seroprevalence data in this population category, it is crucial for public health strategies in Africa. Therefore, this study aims to determine the seroprevalence of SARS-CoV-2 in pregnant women attending antenatal consultations (ANC) in Senegal.

METHODS

This is a retrospective serological study using archived plasma samples collected prospectively, ensuring no redundancies, among pregnant women attending ANC, between March and July 2021 during the Delta wave of COVID-19. Plasma samples were stored at -80 °C until analysis for the presence of IgG and IgM antibodies against SARS-CoV-2 using the WANTAI SARS-CoV-2 Ab ELISA (Wantai Biological Pharmacy Enterprise, Beijing), according to the manufacturer's protocol. Bivariate analysis was conducted to evaluate characteristics associated with seropositivity using JMP® Pro Version 15.0.0 software (SAS Institute Inc., Cary, NC, 1989-2021). For categorical variables with frequencies below 5%, either chi-squared or Fisher tests were applied as appropriate. Significance was defined as p < 0.05 for all tests.

RESULT: A total of 1,227 pregnant women were recruited from five health facilities, including two in Dakar (n = 166) and one in each of the following regional capitals: Saint-Louis (n = 400), Ziguinchor (n = 264), and Kédougou (n = 397). The median age was 25 years [range:18-50]. The overall seroprevalence observed was 64.9% [95% CI: 62.24-67.57], with higher exposure rates in Dakar 71.6% [95% CI: 64.40-77.99], and Ziguinchor 68.1% [95% CI: 62.34-73.51]. Kédougou and Saint-Louis reported 62.9% [95% CI: 58.12-67.58] and 62% [95% CI: 57.15-66.62], respectively. According to age group, the seroprevalence was 62.6% [95% CI: 58.49-66.71], 66.6% [95% CI: 61.62-71.36], 66.3% [95% CI: 59.94-72.24], and 67.2% [95% CI: 58.37-75.01], respectively, for [18-23], [24-29], [30-35], and ≥ 36 years old. Despite these observed variations in the seroprevalence of SARS-CoV-2 across localities, differences are not statistically significant (p = 0.7024).

CONCLUSION

In summary, this study highlights a high seroprevalence of SARS-CoV-2 among pregnant women, with higher exposure rates in Dakar and Ziguinchor. These findings demonstrated that SARS-CoV-2 has spread massively in Senegal, despite few reported cases, similar to trends observed in other African countries. Ultimately, this study reveals seroepidemiological data for SARS-CoV-2 in pregnant women, previously unknown at the national level.