The Post-Vaccination Quantitative Total Immunoglobulin Levels against SARS-CoV-2 in Healthcare Workers: A Multi-Centric Cohort Study in India

Healthcare workers (HCWs) in India received the AZD1222 and BBV152 vaccines from January 2021 onwards. The objective of this study was to compare the immune response (seropositivity rate and geometric mean titer (GMT), and 95% confidence interval (CI)] against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in HCWs who received these vaccines, after the first and second doses. Therefore, the total immunoglobulin (Ig) levels specific to SARS-CoV-2 were measured using quantitative enzyme-linked immunosorbent assay (ELISA). The study population of 133 HCWs consisted of two groups in which the immune response was measured for the AZD1222 and BBV152 vaccines. Data collection was performed from 6 February to 20 August 2021. Four weeks after the first and second dose, the odds ratio of seroconversion for AZD1222 and BBV152 vaccine was 10.3 times (95% CI: 4.5–23.7) and 15.9 times (95% CI: 6.3–39.9), respectively. The GMT was 6392.93 and 6398.82 U/mL for AZD1222 and 1480.47 and 990.38 U/mL for BBV152 after the first and second doses, respectively. Both vaccines elicited an immune response, but the seroconversion rate and GMT after each dose were significantly higher for AZD1222 than those for the BBV152 vaccine in this study.