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 delta

See all studies

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


Bajema K, MMWR, 2021

Full text
Commentary
Test-negative Delta U.S. veterans hospitalized at five Veterans Affairs Medical Centers (VAMCs) in USA. RNA based vaccine mRNA-1273 No vaccine Extraction in progress

Full description

RNA based vaccine BNT162b2 No vaccine Extraction in progress
RNA based vaccine BNT162b2 or mRNA-1273 No vaccine Extraction in progress


Bar-On Y, N Engl J Med, 2021

Full text
Commentary
Cohort Delta Israel residents 60 years of age or older who had been fully vaccinated at least 5 months earlier RNA based vaccine BNT162b2 booster BNT162b2 Extraction in progress

Full description



Barlow R, medRxiv, 2021

Full text
Commentary
Commentary
Test-negative Delta Adults (15+ year old) twithout previous SARS-CoV-2 infection hat were tested for SARS-CoV-2 during July 2021 in a single county in USA. RNA based vaccine mRNA-1273 No vaccine Extraction in progress

Full description

RNA based vaccine BNT162b2 or mRNA-1273 No vaccine Extraction in progress
RNA based vaccine BNT162b2 No vaccine Extraction in progress
Non replicating viral vector Ad26.COV2.S No vaccine Extraction in progress


Bhattacharya A, Diabetes Metab Syndr, 2021

Full text
Commentary
Cohort Delta Adults attending a COVID-19 testing clinic and hospitalized COVID-19 patients in a single center in India Any COVID-19 vaccine ChAdOx1 or BBV15 No vaccine
Serious
Details

Full description



Bruxvoort K, SSRN, 2021

Full text
Commentary
Commentary
Cohort Delta Adults aged ≥18 years who are members of Kaiser Permanente Southern California in the USA RNA based vaccine mRNA-1273 No vaccine
Serious
Details

Full description



Corchado-Garcia J, medRxiv, 2021

Full text
Commentary
Cohort Delta Adults who underwent SARS-CoV-2 polymerase chain reaction (PCR) testing in multiple centers in USA Non replicating viral vector Ad26.COV2.S No vaccine Extraction in progress

Full description



Elliott P, medRxiv, 2021

Full text
Commentary
Commentary
Ecological Delta Adults aged 18 to 64 years In England, UK. Any COVID-19 vaccine BNT162b2 or mRNA-1273 or ChAdOx1 No vaccine Extraction in progress

Full description



Fowlkes A, MMWR, 2021
New

Full text
Cohort Delta Adults with occupation involving regular direct contact (within three feet) with others, ) Any COVID-19 vaccine BNT162b2 or mRNA-1273 or Ad26.COV2.S No vaccine Extraction in progress

Full description



Goldberg Y, medRxiv, 2021

Full text
Commentary
Commentary
Cohort Delta Elderly ages 60 and up who became fully vaccinated between January 16-31, 2021 and without previous SARS-CoV-2 infection in multiple centres in Israel RNA based vaccine BNT162b2 No vaccine
Serious
Details

Full description



Grannis S, MMWR, 2021

Full text
Commentary
Test-negative Delta Adults hospitalized with COVID-19-like illness in 9 states in multiple centres in USA RNA based vaccine mRNA-1273 No vaccine Extraction in progress

Full description

Any COVID-19 vaccine BNT162b2 or mRNA-1273 or Ad26.COV2.S No vaccine Extraction in progress
RNA based vaccine BNT162b2 No vaccine Extraction in progress
Non replicating viral vector Ad26.COV2.S No vaccine Extraction in progress


Griffin J, MMWR, 2021

Full text
Commentary
Cohort Delta All aged 12 and up residents of Los Angeles County in multiple centres in USA Any COVID-19 vaccine BNT162b2 or mRNA-1273 or Ad26.COV2.S No vaccine Extraction in progress

Full description



Israeli Ministry of Health, *, 2021

Full text
Cohort Delta All residents aged 16 years and older in Israel RNA based vaccine BNT162b2 No vaccine Extraction in progress

Full description



Kang M, SSRN, 2021

Full text
Commentary
Commentary
Commentary
Cohort Delta Close contacts of confirmed COVID cases during an outbreak in China Inactivated virus HB02/WIV04/CoronaVac/BICV No vaccine
Serious
Details

Full description



Li N-X, Emerg Microbes Infec, 2021

Full text
Commentary
Test-negative Delta Adults aged 18-59 years undergoing PCR testing in China. Inactivated virus HB02 or WIV04 or CoronaVac No vaccine
Serious
Details

Full description



Lopez J, N Engl J Med, 2021

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

Full description

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


Nanduri S, MMWR, 2021

Full text
Commentary
Cohort Delta Residents at 14,917 nursing homes in the USA RNA based vaccine mRNA-1273 No vaccine
Serious
Details

Full description

RNA based vaccine BNT162b2 or mRNA-1273 No vaccine
Serious
Details
RNA based vaccine BNT162b2 No vaccine
Serious
Details


Nasreen S, medRxiv, 2021

Full text
Commentary
Commentary
Test-negative Delta 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


Nunes B, medRxiv, 2021
New

Full text
Commentary
Commentary
Cohort Delta Older adults aged 65 to 79 without previous SARS-CoV-2 infection living in the community in mainland Portugal * BNT162b2 or mRNA-1273 No vaccine Extraction in progress

Full description



Patalon T, medRxiv, 2021

Full text
Commentary
Commentary
Test-negative Delta Aged 40 and up Maccabi Healthcare Services members in multiple centres in Israel RNA based vaccine BNT162b2 booster BNT162b2 Extraction in progress

Full description

ISRCTN21086382

Pouwels K, medRxiv, 2021

Full text
Commentary
Cohort Delta Adults from households randomly selected across the UK. RNA based vaccine mRNA-1273 No vaccine
Moderate
Details

Full description

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


Pramod S, medRxiv, 2021

Full text
Commentary
Commentary
Test-negative Delta Health care workers at a single center in India Non replicating viral vector ChAdOx1-S No vaccine
Serious
Details

Full description



Puranik A, medRxiv, 2021

Full text
Commentary
Commentary
Cohort Delta Adults who underwent SARS-CoV-2 polymerase chain reaction (PCR) testing in multiple centers in USA RNA based vaccine mRNA-1273 No vaccine
Serious
Details

Full description

RNA based vaccine mRNA-1273 BNT162b2
Serious
Details
RNA based vaccine BNT162b2 No vaccine
Serious
Details


Rosenberg E, MMWR, 2021
Updated

Full text
Full text
Commentary
Cohort Delta Adults aged ≥18 years residing in New York state in multiple centres in USA Any COVID-19 vaccine BNT162b2 or mRNA-1273 or Ad26.COV2.S No vaccine
Serious
Details

Full description



Seppala E, Euro Surveill, 2021

Full text
Commentary
Cohort Delta All adults aged 18 years or older with no prior SARS-CoV-2 infection with a national identification number registered in multiple centres in Norway RNA based vaccine BNT162b2 or mRNA-1273 No vaccine
Serious
Details

Full description



Sheikh A, Lancet, 2021

Full text
Commentary
Test-negative Delta 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


Stowe J, PHE Publishing, 2021

Full text
Commentary
Test-negative Delta Symptomatic COVID-19 patients Non replicating viral vector ChAdOx1-S No vaccine
Moderate
Details

Full description

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


Tang P, medRxiv, 2021

Full text
Commentary
Commentary
Test-negative Delta Resident population in multiple centres in Qatar RNA based vaccine mRNA-1273 No vaccine
Serious
Details

Full description

RNA based vaccine BNT162b2 or mRNA-1273 No vaccine
Serious
Details
RNA based vaccine BNT162b2 No vaccine
Serious
Details
NCT04848584

Tartof S, SSRN, 2021

Full text
Commentary
Commentary
Cohort Delta Kaiser Permanente Southern California healthcare system members aged 12 and up in multiple centres in USA RNA based vaccine BNT162b2 No vaccine
Serious
Details

Full description



Tenforde M, MMWR, 2021
New

Full text
Commentary
Cohort Delta Hospitalized adults at 21 centers in the USA RNA based vaccine BNT162b2 or mRNA-1273 No vaccine Extraction in progress

Full description



Thiruvengadam R, SSRN, 2021

Full text
Commentary
Commentary
Test-negative Delta Individuals attending for RT-PCR testing for suspected SARS-CoV-2 infection at 2 centers in India Non replicating viral vector ChAdOx1-S No vaccine
Serious
Details

Full description



Thompson M, N Engl J Med, 2021

Full text
Commentary
Commentary
Test-negative Delta Adults ≥50 years with Covid-19–like illness at multiple sites in the USA RNA based vaccine mRNA-1273 No vaccine
Moderate
Details

Full description

RNA based vaccine BNT162b2 or mRNA-1273 No vaccine
Moderate
Details
RNA based vaccine BNT162b2 No vaccine
Moderate
Details
Non replicating viral vector Ad26.COV2.S No vaccine
Moderate
Details


Vaishya R, SSRN, 2021

Full text
Commentary
Commentary
Cohort Delta Vaccinated healthcare workers in 43 hospitals in 24 Indian cities Non replicating viral vector ChAdOx1-S Whole-Virion Inactivated Vero Cell (BBV152)
Serious
Details

Full description