Effectiveness of the WHO-authorized Covid-19 Vaccines: a Rapid Review of Global Reports till June 30, 2021

Abstract

Objective Large clinical trials have proved the efficacy of Covid-19 vaccine, and the number of literature about the effectiveness is rapidly growing in the first half of year after mass vaccination was administrated globally. This rapid review aims to provide evidence syntheses as a means to complement the current evidence on the vaccine effectiveness (VE) against various outcomes in real-world settings. Methods This review is conducted based on the updated guideline of PRISMA 2020. Databases (PubMed, EMBASE, and MedRxiv) were searched up to 30 June 2021, (PROSPERO ID: 266866). The studies that assessed the VE of the 6 WHO-authorized vaccines (BNT162b2, ChAdOx1, Ad26.COV2.S, mRNA-1273, BBIBP-CorV, and CoronaVac) were eligible to be included. Quality assessment was performed based on ROBINS-I by 2 independent reviewers. Findings A total of 39 studies were included, covering over 15 million of participants from 11 nations. Among the general population after 2 doses of vaccination, the VE against symptomatic SARS-CoV-2 infection was estimated at 89%–97%, 92% (95% CI, 78%–97%) and 94% (95% CI, 86%–97%) for BNT162b2, ChAdOx1 and mRNA-1273, respectively. As for the protective effects against B.1.617.2 related symptomatic infection, the VE was 88% (95% CI, 85.3%–90.1%) by BNT162b2 and 67.0% (95% CI, 61.3%–71.8%) by ChAdOx1 after fully vaccination. Conclusion This review revealed a consistently high effectiveness of vaccines among the general population in real-world settings. Further studies are needed to provide the information on different races/ethnicity, the effects against SARS-CoV-2 variants, and the duration of protection with longer study time.