Serious adverse events following immunization and predictors of mortality associated with COVID-19 vaccination in India: a secondary data analysis of nationwide causality assessments.

Abstract

Background: Vaccines against COVID-19 were viewed as a way out to the ongoing pandemic and were given the emergency use authorization in India to initiate mass vaccination in January 2021. This study aimed to investigate the serious adverse events following immunizations (AEFIs) reported for COVID-19 vaccines and to identify predictors of mortality among these cases from India.

Methods: A secondary data analysis was conducted on the causality assessment reports for the 2708 serious AEFIs published by the National AEFI Committee under the Immunization Division, Ministry of Health and Family Welfare, Government of India. The analysis included all 21 reports published up until May 2023. The primary outcome variable analyzed was the survival/death status of each AEFI case, with various covariates from the published documents considered in the analysis.

Results: The majority of the serious AEFIs assessed were either coincidental (1220, 45%) or undetermined/unclassifiable (781, 28.8%). The majority of the serious AEFIs were reported among recipients of Covishield (1891, 69.8%) followed by Covaxin (347, 12.8%). Among these, 1114 (42.1%) died while the remaining 1594 (58.9%) were hospitalized and recovered. Systematically, AEFIs involving the cardiovascular system (696, 31.3%) were the most common, followed by those affecting the respiratory system (288, 13%) and neuropsychiatric system (295, 13.3%) which had a significant association with age (p < 0.001) and gender (p < 0.001). On multivariable analysis, females (p = 0.001), younger age groups (p < 0.001), AEFIs whose causality was determined and classified (p < 0.001), AEFI involving gastrointestinal and neuropsychiatric system (p < 0.001), AEFIs reported from North and Western India (p = 0.001) and those occurring during the winter season (p < 0.05) had significantly lower odds of mortality.

Conclusion: Among the cohort of serious AEFIs reported, older age, male sex, undetermined or unclassifiable causality classification, and involvement of the cardiovascular system were associated with significantly higher odds of mortality and require close monitoring following vaccination.