Seroprevalence of anti-severe acute respiratory syndrome coronavirus 2 antibody among healthy blood donors in a hospital-based blood center in Eastern India during the COVID-19 pandemic

BACKGROUND: Few international studies have reported the prevalence of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in healthy, asymptomatic blood donors. These findings have definitely raised queries regarding blood safety and transfusion-transmitted coronavirus disease (COVID)-19. We conducted this first anti-SARS-CoV-2 seroprevalence survey among the healthy blood donors in Eastern India. MATERIALS AND METHODS: The study included 611 healthy blood donors who donated whole blood (WB) in our blood center. For detailed analysis, social and demographic details of all donors like gender, age, weight, occupation, and place of residence were included. Donor eligibility criteria for WB donation were followed as per existing national guidelines. Residual serum samples leftover after screening the mandatory infectious markers were tested for the presence of anti-SARS-CoV-2 IgG directed against domain S1 and S2 of the SARS-CoV-2 spike protein using automated enhanced chemiluminescence technology following the manufacturer's instructions. RESULTS: The mean overall seroprevalence of anti-SARS-CoV-2 antibody in blood donors was observed to be 4.4% (95% confidence interval 3.8–4.9) with a monthly increasing trend. Seroprevalence adjusted for sensitivity and specificity of the assay was 4.1%. The mean S/Co values of reactive donor samples were observed to be 2.99 and 3.42 in June and July 2020, respectively (P = 0.013). No significant variation in seroprevalence rate was observed among donor variables like donor age, gender, profession, and educational qualification. A higher significant prevalence of antibody was observed among voluntary donors and donors residing in suburban areas (P < 0.05). Among the ABO blood groups, no statistical significance of seroprevalences was observed among the various ABO blood groups. CONCLUSION: We conclude that despite many limitations in the current study, we found 4.4% seroprevalence of anti-SARS-CoV-2 antibody in the asymptomatic, healthy, epidemiologically, and medically screened blood donors. These data are definitely the tip of an iceberg and signify much higher seroprevalence in the normal population and indicate that protective measures like masking and social distancing should remain implemented for a long term.