Serological Survey in a university community after the fourth wave of COVID-19 in Senegal

Abstract

Cross-sectional survey was conducted to assess the true extent of COVID-19 exposure among students and staff of Polytechnic High School (PHS). Random cluster sampling was carried out between May 19 and August 18, 2022, after the fourth wave of COVID-19 transmission. IgM and IgG SARS-CoV-2 antibodies were screened using WANTAI SARS-CoV-2 ELISA assays. Seroprevalence and descriptive statistics were calculated. Moreover, the associations between seropositivity and different factors (age, gender, preventive, etc.) were determined using logistic regression. A total of 637 participants were recruited, including 563 students, followed by 52 TAS officers, and 22 professors. The median age among was 21 years [18 - 63]. 62.0% of the participants were female, and 36.89% were male, with a male-to-female ratio = 0.59. The overall IgG and IgM seroprevalence were 92% and 6.91% respectively. We found a higher IgM seroprevalence in men than women (9.4% vs. 5.6%) and a lower IgM seroprevalence in (18-25) age group compared to (55-65) years. Low compliance with preventive measures was found with a significant IgM seroprevalence depending on non-respect of social distancing (p = 0.008). IgM seropositivity was associated with Body Mass Indice (BMI) categorized (O.R. 0.238, p = 0.043), ethnic group (O.R. 0.723, p = 0.046) and marital status (O.R. 2.399, p = 0.021). Moreover, IgG seropositivity was associated with vaccination status (O.R. 4.741, p < 0.001). Our study revealed that the majority of students and staff have already been exposed to SARS-CoV-2, which confirms the circulation of SARS-CoV-2 in PHS at the time of the survey. Our results underline the importance of seroepidemiological surveys to estimate the real impact of the COVID-19 pandemic in a community and to monitor disparities in antibody response in the population.