Chart aggregating vaccine efficacy & effectiveness figures against Alpha, Beta, Delta, Gamma variants of the SARS-CoV-2 coronavirus from a multitude of sources.
We reviewed all available publications, studies, reports and news articles (as of 30th July 2021), sourcing back to original studies where possible.
Where disparate sources cited different figures, we used the average of the range.
Major sources were Public Health England, New England Journal of Medicine, The Lancet, Institute for Health Metrics & Evaluation (IMHE), Centers for Disease Control, New York Times, and the excellent updates of Eric Topol. See the data doc for a full list of studies and articles.
Research issues & challenges
Not all studies specifically cite the variant. For those, we used the @IMHE_UW method: using “the study location as a proxy for the predominant variant [at the time]. eg. studies in S. Africa were assumed to represent efficacy against B.1.351”. (ref)
Not all media reports differentiate between vaccine protection against ‘symptomatic disease’ and ‘severe COVID & hospitalisation’ when citing % figures.
Nor do they necessarily differentiate between vaccine *efficacy* (performance in clinical trials) and *effectiveness* (real world performance). So it’s a bit of mush that’s taken us three weeks or so to pick apart & distill.
We’ll keep this updated with any major studies or new numbers as they emerge.
More sources in the data doc