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Meta-Analysis
. 2021 Jul 5;10(1):94.
doi: 10.1186/s40249-021-00878-5.

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

Musha Chen #  1 , Yue Yuan #  1 , Yiguo Zhou #  1 , Zhaomin Deng  1 , Jin Zhao  1 , Fengling Feng  1 , Huachun Zou  2   3 , Caijun Sun  4   5
Affiliations
Meta-Analysis

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

Musha Chen et al. Infect Dis Poverty. .

Abstract

Background: Various 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 text: A 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).

Conclusions: 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 AEFI. Long-term surveillance of vaccine safety is required, especially among elderly people with underlying medical conditions.

Keywords: Adverse events following immunization; COVID-19 vaccine; Meta-analysis; Randomized controlled trial; Safety.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1
Fig. 1
Selection of reports for inclusion in this systematic review
Fig. 2
Fig. 2
Incidence of adverse events following immunization for different vaccine modalities. BBBIBP-CorV designed by the Beijing Institute of Biological Products; WCoronaVac designed by the Wuhan Institute of Biological Products; †COVID-19 vaccines in the Phase I Trial; ‡COVID-19 vaccines in the Phase II Trial; *COVID-19 vaccines on first vaccination; **COVID-19 vaccines on second vaccination; b1BNT162b1 in the Phase I Trial; b2BNT162b2 in the Phase I Trial. RR risk ratio, CI confidence interval, mRNA messenger ribonucleic acid
Fig. 3
Fig. 3
Adverse reactions to the first dose and second dose of COVID-19 vaccines. †COVID-19 vaccines in the Phase I Trial; ‡COVID-19 vaccines in the Phase II Trial. CI confidence interval, mRNA messenger ribonucleic acid
Fig. 4
Fig. 4
Adverse reactions to COVID-19 vaccines between population aged ≤ 55 years and population aged ≥ 56 years. *COVID-19 vaccines on first vaccination; **COVID-19 vaccines on second vaccination; b1BNT162b1 in the Phase I Trial; b2BNT162b2 in the Phase I Trial. CI confidence interval, mRNA messenger ribonucleic acid
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