Prevalence and determinants of adverse events following ChAdOx1 nCoV-19 vaccination (COVISHIELD) – A retrospective cohort study among healthcare workers in central Karnataka, India

Abstract

Background: India has launched COVID vaccination program on January 16, 2021 and precautionary dose (third dose) on January 10, 2022. Our study evaluated adverse events following immunization (AEFI) among healthcare workers (HCWs) following first, second, and precautionary dose of ChAdOx1 nCoV-19 (COVISHIELD) vaccine. We also evaluated the association of AEFI with the study participants' characteristics. Objectives: (1) To assess the adverse events among HCWs following first, second, and precautionary dose of COVISHIELD vaccine. (2) To determine the factors associated with adverse events of COVISHIELD vaccine. Materials and Methods: A retrospective cohort study was conducted among HCWs of a tertiary care teaching hospital in central Karnataka from January 2021 to June 2022. A semi-structured, pretested questionnaire was used to interview the HCW of tertiary care teaching hospital regarding adverse events following first, second, and precautionary dose of COVISHIELD vaccine; data collected was entered in MS Excel 2019 and analyzed using SPSS v24.0. Results: Among 454 participants majority of them were females (231, 50.88%) and in the age group 18-27 years (151, 33.25%), and the majority were nursing staff (147, 32.37%). Adverse events were reported among 204 (44.93%) following the first dose, 149 (32.81%) after the second dose, and 230 (50.66%) participants following the precautionary dose. Generalized weakness and fever were the common adverse effects reported by participants. Conclusion: Majority of the study population did not report any adverse events following vaccination. Among the study participants who reported adverse events, most events were reported on the same day. Symptoms were mild in severity and short-lived.