Evaluating the seroprevalence of SARS-CoV-2 IgG in five different districts of Bangladesh. A seroepidemiological study

ABSTRACT

Background We aimed to measure the seroprevalences and levels of anti-SARS-CoV-2 IgG in children, unvaccinated and vaccinated adults in five districts of Bangladesh and thus, investigate the association of seroprevalence and anti-SARS-CoV-2 IgG level with respect to different attributes of study participants. Methods In the present study, the seroprevalence of serum anti-SARS-CoV-2 IgG was measured in children (n= 202), unvaccinated adults (n= 112), and vaccinated adults (n= 439) using quantitative ELISA. Results The overall seroprevalence in the three groups of the study participants were 58.3% (90%CrI 52.3-64.2%), 62.2% (90%CrI 54.4-70.0%) and 90.7% (90%CrI 88.3-92.9%), respectively. Multivariate logistic and linear regression revealed no significant association of seropositivity and levels of anti-SARS-CoV-2 IgG with the baseline characteristics of the children. AB blood group (vs A;aOR=0.21, 95% CI 0.04-0.92, p=0.04) and O blood group (vs A;aOR=0.09, 95% CI 0.02-0.32, p=0.0004) were significantly associated with seropositivity in unvaccinated adults after adjusting for confounders. Age (p=0.002) was significantly associated with anti-SARS-CoV-2 level in vaccinated adults after adjusting for confounders. Most of the children and unvaccinated adults belonged to the lower antibody response class which implicates the necessity of vaccination. Conclusion This study portrays a better way of evaluating transmission of virus and gain a better understanding of the true extent of infection as illustrated by the high rates of seroprevalences in children and unvaccinated adults. The findings of this study depicted from the antibody response also suggest the importance of vaccination.