COVID-19 vaccine effectiveness
(Randomized evidence)



Latest news:Last search date July 30, 2023. No further screening is planned after this date. Extraction is ongoing for all pending studies.

  • Results of booster studies are available in the tables below and are updated on a monthly basis.
  • As of December 14, 2022, the COVID-NMA revised its protocol and discontinued the inclusion of prime vaccination trials in its analysis. The analysis presented on this page for prime vaccines compared to placebo or other vaccines includes trials that were identified and included up to December 14, 2022. A list of studies that were eligible up to this date but not extracted is provided in detail here .
  • The vaccine review "Efficacy and safety of COVID‐19 vaccines" included 41 preprints and published trials of 12 different COVID-19 used as prime vaccination and that were published before 5 November 2021.


    Perform your own analysis using COVID-NMA data for prime vaccination (last search date 14/12/2022), create and download your forest plots by clicking below:

    go to metacovid

    COVID-19 PRIME VACCINATION: Last search date December 14, 2022.

    Vaccine efficacy and safety for vaccine vs placebo / no vaccine (forest plots)

    Vaccine efficacy and safety for vaccine vs vaccine (forest plots)

    Vaccine efficacy, immunogenicity and safety of heterologous vs homologous vaccination (tables)