Study of Antibody levels Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) among Health Care Workers of The Indian Tertiary Care Hospital

Background: Health care workers (HCWs) are the frontline workers for suspected and confirmed COVID-19 cases. They are apparently at a higher risk of contracting the disease than the general population and if infected, pose a risk to susceptible patients and colleague of HCWs. The aim of the study was to quantitively measure the antibody levels against SARS-CoV-2 in HCWs of tertiary care hospital. Material and Methods: Study was conducted at a tertiary care hospital in India. Blood samples of 410 individuals were analysed by Chemiluminescence Immunoassay analyser using commercially available kits for in-vitro quantitative determination of antibodies (including IgG) against SARS‑CoV‑2 spike (S) protein's receptor binding domain (RBD). Results: In HCWs, greater antibody response to ChAdOx1 nCoV- 19 Corona Virus Vaccine (Recombinant) than Inactivated (killed) vaccine (median antibody titre - 1147 vs 194 respectively; p ≤ 0.001) was observed. Significant difference (p ≤ 0.001) in antibody levels of HCWs between those who received vaccination and never acquired the COVID-19 and those HCWs who received vaccination but were previously infected with SARS-CoV-2 after one or two doses of vaccination (278, 100 respectively; median antibodies - 363 vs 1292; p-value = 0.05) was found.