Abstract
Nowadays, the vaccination with COVID-19 vaccines is being promoted worldwide, professionals and common people are very concerned about the efficacy and safety of COVID-19 vaccines. No published systematic review and meta-analysis has assessed the efficacy and safety of the COVID-19 vaccines based on data from phase III clinical trials. Therefore, this study has estimated the efficacy and safety of COVID-19 vaccines and the differences between vaccine types. PubMed, Embase, the Cochrane Library, CNKI, Wanfang, medRxiv databases and two websites were used to retrieve the studies. Random-effects models were used to estimate the pooled efficacy and safety with risk ratio (RR). A total of eight studies, seven COVID-19 vaccines and 158,204 subjects were included in the meta-analysis. All the vaccines had a good preventive effect on COVID-19 (RR = 0.17, 95% CI: 0.09–0.32), and the mRNA vaccine (RR = 0.05, 95% CI: 0.03–0.09) was the most effective against COVID-19, while the inactivated vaccine (RR = 0.32, 95% CI: 0.19–0.54) was the least. In terms of safety, the risk of overall adverse events showed an increase in the vaccine group after the first (RR = 1.46, 95% CI: 1.03–2.05) or second (RR = 1.52, 95% CI: 1.04–2.20) injection. However, compared with the first injection, the risk of local (RR = 2.64, 95% CI: 1.02–6.83 vs. RR = 2.25, 95% CI: 0.52–9.75) and systemic (RR = 1.33, 95% CI: 1.21–1.46 vs. RR = 1.59, 95% CI: 0.84–3.01) adverse events decreased after the second injection. As for the mRNA vaccine, the risk of overall adverse events increased significantly, compared with the placebo, no matter whether it was the first (RR = 1.83, 95% CI = 1.80–1.86) or the second (RR = 2.16, 95% CI = 2.11–2.20) injection. All the COVID-19 vaccines that have published the data of phase III clinical trials have excellent efficacy, and the risk of adverse events is acceptable. The mRNA vaccines were the most effective against COVID-19, meanwhile the risk and grade of adverse events was minimal, compared to that of severe symptoms induced by COVID-19.
Highlights
In late 2019, a highly transmissible and pathogenic coronavirus emerged, designated as syndrome coronavirus 2 (SARS-CoV-2) and there followed a pandemic of acute respiratory disease, named “coronavirus disease 2019” (COVID-19) [1,2]
The vaccination protocols were similar in these studies, including the injection site, number of vaccine injections, the period of follow-up, primary end-point events, and the recorded adverse events
Virus-vectored vaccines reduced the risk of serious adverse events (RR = 0.79, 95% CI: 0.63–0.99). In this meta-analysis of RCTs, we found that the seven COVID-19 vaccines had excellent efficacy and safety
Summary
In late 2019, a highly transmissible and pathogenic coronavirus emerged, designated as syndrome coronavirus 2 (SARS-CoV-2) and there followed a pandemic of acute respiratory disease, named “coronavirus disease 2019” (COVID-19) [1,2]. As the COVID-19 pandemic continues to rage, promoting the development of effective vaccines is critical to prevent further morbidity and mortality and, hopefully, limit and even stop the worldwide spread of COVID-19 [4,5]. The rapid increase in morbidity and mortality of the COVID-19 pandemic has led to a drastic shift in the conventional vaccine development paradigm and timelines from a time frame of 10–15 years to 1–2 years [6]. At least eight COVID-19 vaccines have been granted emergency use and/or full marketing authorization by the regulatory authorities, namely CoronaVac, HB02 (BBIBP-CorV), AZD1222 (ChAdOx1-S), Sputnik V (Gam-COVID-Vac), Ad26.COV2.S, BBV152, BNT162b2 and mRNA-1273 [4,9,10]. Most countries are promoting vaccination against COVID-19, such as USA, China, India, and Brazil
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