Abstract
This systematic review and meta-analysis was conducted to compare the safety and efficacy of 2019 novel coronavirus disease (COVID-19) vaccines according to vaccine platform and severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) infection severity. Articles published between 24 January 2020 and 30 May 2021 were retrieved via a PubMed and EMBASE search. A total of 12 reports on phase-3 clinical trials and observational studies of COVID-19 vaccines were included in the review. In terms of vaccine safety, mRNA vaccines showed more relevance to serious adverse events than viral vector and inactivated vaccines, but no solid evidence indicated that COVID-19 vaccines directly caused serious adverse events. Serious metabolic, musculoskeletal, immune-system, and renal disorders were more common among inactivated vaccine recipients, and serious gastrointestinal complications and infections were more common among viral vector and inactivated vaccine recipients. The occurrence of serious vessel disorders was more frequent in mRNA vaccines. In terms of efficacy, two mRNA vaccine doses conferred a lesser risk of SARS-COV-2 infection (odds ratio: 0.05; 95% confidence interval: 0.02–0.13) than did vaccination with viral vector and inactivated vaccines. All vaccines protected more against symptomatic than asymptomatic cases (risk ratio, 0.11 vs. 0.34), but reduced the risk of severe SARS-COV-2 infection. The COVID-19 vaccines assessed in this study are sufficiently safe and effective. The results indicate that two mRNA vaccine doses prevent SARS-COV-2 infection most effectively, but further research is needed due to the high degree of heterogeneity among studies in this sample. Interventions should be implemented continuously to reduce the risks of infection after one vaccine dose and asymptomatic infection.
Highlights
The 2019 coronavirus disease (COVID-19) was first identified in Wuhan, China, in December of that year
The keywords used for the PubMed search were “COVID19 vaccine*” AND [(Efficacy odds ratios (ORs) Effectiveness) OR Safety], and the subheadings used for the EMBASE search were AND
This systematic review and meta-analysis were conducted to explore the associations of COVID-19 vaccines with the occurrence of serious adverse events, and to compare the protection provided by different COVID-19 vaccines and the vaccines’ efficacy against different infection types
Summary
The 2019 coronavirus disease (COVID-19) was first identified in Wuhan, China, in December of that year. COVID-19 is caused by a novel coronavirus [severe acute respiratory syndrome coronavirus 2 (SARS-COV-2)], similar to the other two coronaviruses—SARSCoV and MERS-CoV [1]. Compared with SARS, MERS and influenza, COVID-19 is transmitted more from human to human through droplets and has a higher infection rate, but a lower mortality rate [1]. Given these properties, it spread from its origin to other regions and countries at unexpected speed, causing a global pandemic. More than 100 million people have been infected globally, and about 2.9 million deaths have been registered globally; this disease has posed an enormous challenge to health systems worldwide [3]
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