Effect of the Previous History of the SARS-CoV-2 Infections on Antibody Levels among Sputnik V Vaccinated Healthcare Workers.

Abstract

Measuring the level of antibodies produced post-vaccination in response to the SARS-CoV-2 spike protein is considered a strategy for estimating the effectiveness of the COVID-19 vaccines. To examine the antibody levels among the healthcare workers in different hospitals in Mashhad, Iran after receiving the second dose of Sputnik V. In this study, we enrolled 230 healthcare workers for evaluating the Gam-COVID-Vac or Sputnik V after the second administration in different hospitals in Mashhad. Antibody levels of spike protein were quantitatively evaluated in a sample of 230 negative RT-PCR tests for the COVID-19 individuals. The analysis has been done based on an immunological assay using enzyme-linked immunosorbent assay (ELISA). The infection history of the subjects and their families was examined through their medical records. Our results demonstrated a significant association between a higher titer of IgG and a previous history of the COVID-19 infection (P<0.001). Moreover, the chance of detecting antibodies titer more than 50 AU/ml was 16.99 in these people which was significantly higher than in people without a history of infection pre-vaccination [%95CI: (7.38,39.12), P<0.001]. This result demonstrates that the efficacy of antibody production is related to the previous history of the SARS-CoV-2 infections. Ongoing monitoring of the level of antibody among vaccinated populations will help evaluating the effect of vaccines on humoral immunity status.