COVID-19 vaccine effectiveness on variants of concern

Observational studies

Protocol

Our protocol is available on Zenodo here .

Variants of concern

We identified observational studies assessing vaccine effectiveness on variant from the studies identified by Krause P et al. Lancet 2021 and the process described in our protocol .

Vaccine effectiveness is based on direct evidence but also indirect evidence (i.e., variant exposure extrapolated the prevalence of the variant in the population) reported in the manuscript or in secondary sources.

Risk of bias assessment is ongoing and may be missing on the forest plots.

Studies for variant gamma

See all studies

Trial Design Variant Participants Comparisons
Type Intervention 1 Intervention 2 Overall risk
of bias
Highest assessment
Full description


Hitchings M, Lancet Reg Health Am, 2021

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Commentary
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Test-negative Gamma All healthcare workers, including in hospitals, primary care, general, and specialized units Inactivated virus CoronaVac No vaccine
Moderate
Details

Full description



Ranzani O, medRxiv, 2021

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Test-negative Gamma Adults ≥70 years of age, residents of São Paulo State and who underwent SARS-CoV-2 RT-PCR testing in multiple centers in Brazil Inactivated virus CoronaVac No vaccine
Serious
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Skowronski D, Clin Infect Dis, 2021

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Test-negative Gamma Elderly aged 70 and older in communities in British Colombia, Canada RNA based vaccine BNT162b2 or mRNA-1273 No vaccine
Serious
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Yassi A, PLoS ONE, 2021

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Cohort Gamma Healthcare workers in Vancouver, Canada RNA based vaccine BNT162b2 or mRNA-1273 No vaccine
Serious
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Full description