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.

Analyses for variant delta and Beta were updated, some studies are awaiting classification ( last search date 24 sep, 2021).

Analyses for other variants of concern are not up to date; data extraction is in process.

Studies for variant alpha

See all studies

Trial Design Variant Participants Comparisons
Type Intervention 1 Intervention 2 Overall risk
of bias
Highest assessment
Full description
NCT04607941

Charmet T, Lancet Reg Health Eu, 2021

Full text
Commentary
Case-control Alpha Adults in France with or without prior history of infection (>2 months previous to index infection) RNA based vaccine BNT162b2 No vaccine
Serious
Details

Full description



Dagan N, N Engl J Med, 2021

Full text
Commentary
Cohort Alpha Individuals 16 years and older with no previous documented infection with SARS-CoV-2 (PCR) in Israel RNA based vaccine BNT162b2 No vaccine
Moderate
Details

Full description



Lopez Bernal J, BMJ, 2021

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Commentary
Commentary
Test-negative Alpha Adults aged 70 years and older who reported symptoms of COVID-19 Non replicating viral vector ChAdOx1-S No vaccine
Serious
Details

Full description

RNA based vaccine BNT162b2 No vaccine
Serious
Details


Lopez J, N Engl J Med, 2021

Full text
Commentary
Test-negative Alpha Data on all symptomatic sequenced cases of COVID-19 in England Non replicating viral vector ChAdOx1-S No vaccine
Serious
Details

Full description

Any COVID-19 vaccine BNT162b2 or ChAdOx1-S No vaccine
Serious
Details
RNA based vaccine BNT162b2 No vaccine
Serious
Details


Nasreen S, medRxiv, 2021

Full text
Commentary
Commentary
Test-negative Alpha Symptomatic community-dwelling individuals aged ≥16 years with no history of SARS-CoV-2 infection in Canada RNA based vaccine mRNA-1273 No vaccine
Serious
Details

Full description

Non replicating viral vector ChAdOx1-S No vaccine
Serious
Details
RNA based vaccine BNT162b2 No vaccine
Serious
Details


Sheikh A, Lancet, 2021

Full text
Commentary
Test-negative Alpha People of all ages tested for COVID-19 by RT-PCR in Scotland Non replicating viral vector ChAdOx1-S No vaccine
Serious
Details

Full description

RNA based vaccine BNT162b2 No vaccine
Serious
Details