Evaluation of antibodies against SARS-CoV-2 and their patterns of response in health care workers and general population at a tertiary care Centre

Abstract

SARS-CoV-2 (previously called 2019-nCoV), and was named in February 2020 as COVID-19 by the WHO. Estimate the seroprevalence of antibodies against SARS-CoV-2 in health care workers (HCW) and general population in the first and second wave and assess the pattern of antibody response in HCW with COVID-19 infected and non-infected over pre and post-vaccination. This was a cohort observational retrospective study done to analyse the seroprevalence in HCW from July-September 2020, in the general population in the first wave (December 2020–February 2021) and second wave (March–September 2021). SARS-CoV-2 testing by RT-PCR (QIAGEN Company). Testing for quantitative IgG and IgM (Abbott) antibodies, Total Antibodies (Roche), Anti-SARS-CoV-2 IgG RBD(Roche), and Anti-SARS-CoV-2 IgG S1/S2 (Diasorin XL), to assess the pattern of antibody responses categorized as baseline (before the first dose), 14 days after 1st dose, before 2nd dose (45 days post first dose), 14 days post-second dose. Among 1340 HCW, 1268 underwent RT-PCR testing, 540 serology testing and 431 underwent both testing. We identified 164 of 1268 positive RT-PCR and using serology testing 229 of 540 were seropositive. High seropositivity was observed in age group 26-45 years (44.9%) HCW, in males (65.9%), nurses (47.3%), and ward staff (48.6%). High seroprevalence in general population-76.07% in the 2nd wave compared to 1st wave (44.67%). SARS-CoV-2 antibodies showed gender associated seroprevalence and higher immune response was observed in COVID-19 infected than in non-infected HCW pre- and post-vaccination.