Adverse reaction characteristics of five COVID-19 vaccines across different technology platforms: a pooled analysis of nine clinical trials.

Background: Evidence regarding the comparative safety of different COVID-19 vaccines remains limited. This study aims to characterize and compare the safety profiles of five COVID-19 vaccines in terms of adverse reactions after immunization.

Research design and methods: We conducted a retrospective analysis of adverse reactions reported among adults aged 18-59 years from nine clinical trials. The analyzed vaccines included inactivated, recombinant protein, intranasal influenza-vectored, aerosolized and intramuscular Ad5 vectored COVID-19 vaccines. Factor analysis and association rule analysis were used to characterize adverse reaction patterns, while multivariate logistic regression was employed to assess the influence of vaccine type and demographic factors.

Results: Inactivated, recombinant, and intramuscular Ad5 vectored vaccines commonly caused injection site pain, fatigue, headache, and pyrexia from the SOC of 'General disorders and administration site conditions.' Intranasal influenza-vectored vaccines mainly cause respiratory symptoms such as rhinorrhea and nasal congestion, while dry mouth and oropharyngeal pain from 'Gastrointestinal disorders' were primarily observed in aerosolized Ad5 vectored vaccines. Younger age (p < 0.001), female sex (p = 0.001), comorbidities (p < 0.001), and intramuscular Ad5 vectored vaccines (p < 0.001) were significantly associated with higher adverse reaction risks.

Conclusions: COVID-19 vaccines developed through different technological approaches have distinct adverse reaction profiles.