Safety of SARS-CoV-2 vaccines: a systematic review and meta-analysis of randomized controlled trials

BackgroundVarious modalities of vaccines against coronavirus disease 2019 (COVID-19), based on different platforms and immunization procedures, have been successively approved for marketing worldwide. A comprehensive review for clinical trials assessing the safety of COVID-19 vaccines is urgently needed to make an accurate judgment for mass vaccination.Main textA systematic review and meta-analysis was conducted to determine the safety of COVID-19 vaccine candidates in randomized controlled trials (RCTs). Data search was performed in PubMed, Embase, Cochrane library, Scopus, Web of Science, and MedRxiv. Included articles were limited to RCTs on COVID-19 vaccines. A total of 73,633 subjects from 14 articles were included to compare the risks of adverse events following immunization (AEFI) after vaccinating different COVID-19 vaccines. Pooled risk ratios (RR) of total AEFI for inactivated vaccine, viral-vectored vaccine, and mRNA vaccine were 1.34 [95% confidence interval (CI) 1.11-1.61, P<0.001], 1.65 (95% CI 1.31-2.07, P<0.001), and 2.01 (95% CI 1.78-2.26, P<0.001), respectively. No significant differences on local and systemic AEFI were found between the first dose and second dose. In addition, people aged 55 years were at significantly higher risk of AEFI than people aged >= 56 years, with a pooled RR of 1.25 (95% CI 1.15-1.35, P<0.001).ConclusionsThe safety and tolerance of current COVID-19 vaccine candidates are acceptable for mass vaccination, with inactivated COVID-19 vaccines candidates having the lowest reported AEFI. Long-term surveillance of vaccine safety is required, especially among elderly people with underlying medical conditions.

Automated summary

A systematic review and meta-analysis found that the safety and tolerance of current COVID-19 vaccine candidates are acceptable for mass vaccination, with inactivated COVID-19 vaccines candidates having the lowest reported adverse events following immunization (AEFI). Long-term surveillance of vaccine safety is required, especially among elderly people with underlying medical conditions.