COVID-19 vaccine effectiveness (VE) evaluations are vital to guide policy and strategy because COVID-19 VE evaluations assess how COVID-19 vaccines work in real-life contexts.

In a living systematic review, results from COVID-19 VE studies are being summarized by the International Vaccine Access Center at Johns Hopkins Bloomberg School of Public Health in collaboration with WHO, with financial support from CEPI. At VIEW-hub, we provide summaries, visuals, and a downloadable database of grey, pre-print, and published literature. Only literature that meets specific criteria are included; the methods are available here. If you are interested in receiving weekly updates of the living systematic review, please make a request at covidve@who.int.

As of end of September 2024, the total number of COVID-19 VE studies is 624 covering 52 countries across the six WHO regions.

The Strategic Advisory Group of Experts on Immunization (SAGE)’s Working Group on COVID-19 Vaccines has published “WHO SAGE roadmap on uses of COVID-19 vaccines in the context of OMICRON and substantial population immunity” that lists questions that need to be answered in order to assist SAGE in formulating policy recommendations for consideration by WHO regarding the use of COVID-19 vaccines.

As of April 2023, at the global level, key questions related to COVID-19 VE include the following:

• specific recommendations for primary series and boosters according to priority-use groups;
• need and frequency for boosters beyond the first booster dose;
• variant-containing vaccines;
• vaccination during pregnancy; and
• post-COVID-19 conditions.

The following protocols can be used to conduct a VE evaluation, though might need to be modified based on the context in which the study is being done:

WHO protocols

External protocols