Efficacy and effectiveness of COVID-19 vaccines against SARS-CoV-2 infection: interim results of a living systematic review, 1 January to 14 May 2021

Euro Surveill. 2021 Jul;26(28):2100563. doi: 10.2807/1560-7917.ES.2021.26.28.2100563.


Evidence on COVID-19 vaccine efficacy/effectiveness (VE) in preventing asymptomatic SARS-CoV-2 infections is needed to guide public health recommendations for vaccinated people. We report interim results of a living systematic review. We identified a total of 30 studies that investigated VE against symptomatic and/or asymptomatic infection. In fully vaccinated individuals, VE against symptomatic and asymptomatic infections was 80-90% in nearly all studies. Fully vaccinated persons are less likely to become infected and contribute to transmission.

Keywords: COVID-19; SARS-CoV-2; systematic review; vaccination; vaccine effectiveness.

Publication types

  • Systematic Review

MeSH terms

  • Asymptomatic Infections
  • COVID-19 Vaccines*
  • COVID-19*
  • Humans
  • SARS-CoV-2


  • COVID-19 Vaccines