COVID-19 vaccine effectiveness on variants of concern

Observational studies

Protocol

Our protocol is available on Zenodo here .

Last search data: Nov 3, 2021.

The project stopped after this date and the analysis presented include eligible studies up to Nov 3, 2021.

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 beta

See all studies

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


Chemaitelly H, N Eng J Med, 2021

Full text
Commentary
Test-negative Beta Adults and children with PCR-confirmed/negative SARS-CoV-2 in Qatar. RNA based vaccine BNT162b2 No vaccine
Serious
Details

Full description



Chemaitelly H, medRxiv, 2021

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Commentary
Cohort Beta Immunosuppressed kidney transplant recipients in Qatar. RNA based vaccine BNT162b2 or mRNA-1273 No vaccine
Moderate
Details

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Chemaitelly H, Nat. Med., 2021

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Test-negative Beta Mainly working-age adults not vaccinated or receiving at least one dose of the mRNA- 1273 vaccine or completed the two-dose regimen RNA based vaccine mRNA-1273 No vaccine
Serious
Details

Full description



Lefevre B, medRxiv, 2021

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Commentary
Cohort Beta Adults including elderly in 5 centres in France. RNA based vaccine BNT162b2 No vaccine
Serious
Details

Full description