Serious adverse events reported from the COVID-19 vaccines: A descriptive study based on WHO database

Background In the light of current pandemic, the emergency approval of few COVID-19 vaccines seems to provide a ray of hope. However, their approval is solely based on limited data available from the clinical trials in a short period of time; thereby imposing a necessity to study the adverse events(AEs) associated with their use. This study therefore aims to assess the Serious Adverse Events (SAEs) associated with various COVID-19 vaccines reported in the WHO database (VigiBase®). Methods The data from VigiBase® was analyzed to assess the reported SAEs linked to various COVID-19 vaccines. The duplicates in the data were removed and were analyzed on the basis of age, gender, and seriousness of adverse events at the System Organ Classification (SOC) level and the individual Preferred Term (PT) level. Results A total 103954 adverse events reported from 32044 subjects were taken for analysis. Of 32044 subjects, majority were females (80%). Also, a total of 28799 (27.7%) SAEs were reported from the 8007 individuals. Most of the SAEs were observed in Europe (83%) amongst females (79.4%) between 18 to 64 years (80.74%) of age. Majority of SAEs (74%) were reported for BNT162b2 (Pfizer) vaccine. On system wise classification, general disorders (30%) were the commonest followed by nervous system (19.1%) and musculoskeletal (11.2%) disorders. In individual category, headache (8.1%) was the commonest, followed by pyrexia (7%) and fatigue (5.1%). The number of SAEs were reported with various vaccines were comparatively lesser as compared to the non-serious ones and incidence of death was low with all the vaccines candidates. Elderly (> 65 years) people reported more serious AEFIs as compared to other age groups. Conclusion The reported SAEs from the COVID–19 vaccines were in line with the data published in clinical trials. To link these SAEs to vaccines will need causality analysis and review of individual reports.