COVID-19 immunoglobulin G antibodies in healthy blood donors paving way to herd immunity

Abstract

Background and Objectives: Herd immunity is the immunity or resistance to particular infection that occurs in group of people when a very high percentage of individuals have been vaccinated or previously exposed to infection. The goal of this study was to assess the development of herd immunity to COVID-19 in parts of Western India. Methods: The study was conducted at a tertiary care hospital in India on routine blood donors who were tested for SARS-CoV-2 immunoglobulin G (IgG) antibody. We systematically investigated 808 healthy donors at various points of time in the 3-month period starting from September 2020 to November 2020 for SARS-CoV-2 seroprevalence. Results: The results of November month show a sudden increase (51.96%) in the later half. The seroprevalence in healthy donors in other towns and cities shows an aggregate average of SARS-CoV-2 IgG antibody 13.59% (200/1472) as against Jaipur city with 36.12% (292/808). Deedwana has higher seropositivity in blood donors 31.5% (24/76) whereas Sujangarh and Jhunjhunu did not have any donors with seropositive status. Conclusion: Our findings could be the tip of iceberg of emerging herd immunity to SARS-CoV-2 infection in India. Future research will determine how long these antibodies will last. Will they be protective toward future COVID-19 infection?