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 included (last update: 2022-06-10)
- Forest plots - RNA based vaccine (last update: 2021-12-02)
- Forest plots - Non replicating viral vector (last update: 2021-12-02)
- Forest plots - Inactivated virus (last update: 2021-12-02)
- Forest plots - Any vaccine (last update: 2021-12-02)
- Forest plots - Booster (last update: 2021-11-26)
- Studies included (last update: 2021-12-13)
- Forest plots - RNA based vaccine (last update: 2021-11-12)
- Forest plots - Non replicating viral vector (last update: 2021-11-12)
- Forest plots - Any vaccine (last update: 2021-11-05)
- Studies included (last update: 2021-10-27)
- Forest plots - RNA based vaccine (last update: 2021-10-28)
- Forest plots - Inactivated virus (last update: 2021-10-14)
- Studies included (last update: 2021-11-15)
- Forest plots - RNA based vaccine (last update: 2021-10-21)
- Studies included (last update: 2024-11-21)
- Forest plots - RNA based vaccine (last update: 2021-10-21)
- Forest plots - Non replicating viral vector (last update: 2021-10-21)
Delta
Alpha
Gamma
Beta
Beta-gamma
Studies for variant delta
| Trial | Design | Variant | Participants | Comparisons | ||||
|---|---|---|---|---|---|---|---|---|
| Type | Intervention 1 | Intervention 2 | Overall risk of bias Highest assessment |
Full description | ||||
|
Andrews N, medRxiv, 2021 Full text Commentary Commentary |
Test-negative | Delta | Adults aged 16 years or older living in England | RNA based vaccine | mRNA-1273 | No vaccine |
Moderate Details |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Moderate Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Moderate Details |
|||||
|
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 |
Moderate Details |
|
| RNA based vaccine | BNT162b2 or mRNA-1273 | No vaccine |
Moderate Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Moderate Details |
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|
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 | Booster | BNT162b2 booster | BNT162b2 |
Serious Details |
|
|
Barda N, Lancet, 2021 Full text (21)02249-2/fulltextCommentary |
Cohort | Delta | Individuals, 16 years or older, that received the second vaccine dose at least 5 months ago in Israel | Booster | BNT162b2 booster | BNT162b2 |
Moderate Details |
|
|
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 |
Serious Details |
|
| RNA based vaccine | BNT162b2 or mRNA-1273 | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Non replicating viral vector | Ad26.COV2.S | No vaccine |
Serious Details |
|||||
|
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-S or BBV152 | No vaccine |
Serious Details |
|
|
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 |
|
|
Bruxvoort K, medRxiv, 2021 Full text Commentary |
Test-negative | Delta | Adults members of an integrated health care system (KPSC) in the USA | RNA based vaccine | mRNA-1273 | No vaccine |
Moderate Details |
|
|
Chadeau-Hyam M, medRxiv, 2021 Full text Commentary Commentary |
Cross-sectional | Delta | Random selection of adults volunteering to provide self-sampled throat and nose swabs in England | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|||||
| Any COVID-19 vaccine | BNT162b2 or mRNA-1273 or ChAdOx1-S | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
|
Chemaitelly H, N Eng J Med, 2021 Full text Commentary |
Test-negative | Delta | Adults and children with PCR-confirmed/negative SARS-CoV-2 in Qatar. | RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|
|
Cohn B, medRxiv, 2021 Full text Commentary Commentary |
Cohort | Delta | Adults aged 18 and older including elderly and co-morbidities in all states and territories of USA | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Non replicating viral vector | Ad26.COV2.S | No vaccine |
Serious Details |
|||||
|
de Gier B, medRxiv, 2021 Full text Commentary Commentary |
Cohort | Delta | Adolescents and adults in the Netherlands | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|||||
| Any COVID-19 vaccine | BNT162b2 or ChAdOx1-S or mRNA-1273 or Ad26.COV2.S | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Non replicating viral vector | Ad26.COV2.S | No vaccine |
Serious Details |
|||||
|
Elliott P, medRxiv, 2021 Full text Commentary Commentary |
Cross-sectional | Delta | Adults aged 18 to 64 years In England, UK. | Any COVID-19 vaccine | BNT162b2 or mRNA-1273 or ChAdOx1-S | No vaccine |
Serious Details |
|
|
Fowlkes A, MMWR, 2021 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 |
Moderate Details |
|
|
Glatman-Freedman A, Emerg Infect Dis, 2021 Full text Commentary |
Cohort | Delta | Adolescents 12–15 years of age with no history of COVID-19 in Israel | RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|
|
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 |
|
|
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 |
Moderate Details |
|
| Any COVID-19 vaccine | BNT162b2 or mRNA-1273 or Ad26.COV2.S | No vaccine |
Moderate Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Moderate Details |
|||||
| Non replicating viral vector | Ad26.COV2.S | No vaccine |
Moderate Details |
|||||
|
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 |
Critical Details |
|
|
Israeli Ministry of Health, *, 2021 Full text |
Cohort | Delta | All residents aged 16 years and older in Israel | RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|
|
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 or WIV04 or CoronaVac or BICV | No vaccine |
Serious Details |
|
|
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 |
|
|
Lin D, medRxiv, 2021 Full text Commentary Commentary |
Cohort | Delta | Residents of North Carolina, USA | RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|
| Non replicating viral vector | Ad26.COV2.S | No vaccine |
Serious Details |
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|
Liu C, medRxiv, 2021 Full text Commentary Commentary |
Cohort | Delta | Adults including elderly and co-morbidities with no history of COVID-19 in multiple centres in New York, USA | RNA based vaccine | BNT162b2 or mRNA-1273 | No vaccine |
Serious Details |
|
|
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 |
|
| Any COVID-19 vaccine | BNT162b2 or ChAdOx1-S | No vaccine |
Moderate Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Moderate Details |
|||||
|
Manley HJ, medRxiv, 2021 ttps://www.medrxiv.org/content/10.1101/2021.09.24.21264081v1Commentary Commentary |
Cohort | Delta | Adult maintenance dialysis (home and in center) without known prior COVID-19 infection treated at Dialysis Clinic, Inc. in USA. | Any COVID-19 vaccine | BNT162b2 or mRNA-1273 or Ad26.COV2.S | No vaccine |
Serious Details |
|
| Vaccine vs vaccine | BNT162b2 | mRNA-1273 |
Serious Details |
|||||
| Vaccine vs vaccine | Ad26.COV2.S | mRNA-1273 |
Serious Details |
|||||
|
Marti-nez Baz I, Euro surveillance, 2021 Full text Commentary |
Cohort | Delta | Close contacts of COVID-19 cases from 1 April to 31 August 2021 in Navarre, Spain. | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Non replicating viral vector | Ad26.COV2.S | No vaccine |
Serious Details |
|||||
|
McKeigue P, medRxiv, 2021 Full text Commentary Commentary |
Case-control | Delta | Population of Scotland | Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|
| RNA based vaccine | BNT162b2 or mRNA-1273 | No vaccine |
Serious Details |
|||||
|
Morgan JA, Obstet Gynecol, 2021 Full text Commentary |
Cohort | Delta | Pregnant women in Louisiana, USA | Any COVID-19 vaccine | BNT162b2 or mRNA-1273 or Ad26.COV2.S | No vaccine |
Serious Details |
|
|
Murugesan M, SSRN, 2021 Full text Commentary Commentary |
Cohort | Delta | Health care workers without previous COVID-19 infection at a single center in Vellore, India. | Any COVID-19 vaccine | ChAdOx1-S or BBV152 | No vaccine |
Serious 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 |
|
| 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 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 |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
|
Nordstrom P, SSRN, 2021 Full text Commentary Commentary |
Cohort | Delta | General population including co-morbidities in Sweden. | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|||||
| Any COVID-19 vaccine | BNT162b2 or mRNA-1273 or ChAdOx1-S | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Heterologous | 1 ChAdOx1-S + 1 BNT162b2 OR 1 mRNA-1273 | No vaccine |
Serious Details |
|||||
|
Nunes B, medRxiv, 2021 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 | RNA based vaccine | BNT162b2 or mRNA-1273 | No vaccine |
Serious Details |
|
|
Patalon T, medRxiv, 2021 Full text Commentary Commentary |
Test-negative | Delta | Aged 40 and up Maccabi Healthcare Services members in multiple centres in Israel | Booster | BNT162b2 booster | BNT162b2 |
Moderate Details |
|
|
Polinski J, medRxiv, 2021 Full text Commentary Commentary |
Cohort | Delta | Adults including elderly and co-morbidities with no history of COVID-19 in multiple centres throughout the USA | Non replicating viral vector | Ad26.COV2.S | No vaccine |
Serious Details |
|
|
ISRCTN21086382 Pouwels K, Nat Med, 2021 Full text Full text Commentary Commentary |
Cohort | Delta | Adults from households randomly selected across the UK. | RNA based vaccine | mRNA-1273 | No vaccine |
Moderate Details |
|
| 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 |
|
|
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 |
|
| Vaccine vs vaccine | mRNA-1273 | BNT162b2 |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
|
Ranzani OT, medRxiv, 2021 Full text |
Test-negative | Delta | RT-PCR from adults residing in Mato-Grosso do Sul | Non replicating viral vector | Ad26.COV2.S | No vaccine |
Moderate Details |
|
|
Robles-Fontan M, medRxiv, 2021 Full text Commentary Commentary |
Cohort | Delta | General population of Puerto Rico aged 12 years and older | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Non replicating viral vector | Ad26.COV2.S | No vaccine |
Serious Details |
|||||
|
Rosenberg E, MMWR, 2021 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 |
|
|
Self WH, MMWR, 2021 Full text |
Test-negative | Delta | Adults hospitalized with COVID-19 like illness without Immunocompromising conditions living in United States, | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Non replicating viral vector | Ad26.COV2.S | No vaccine |
Serious Details |
|||||
|
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 |
|
|
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 |
|
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
|
Singh C, Epidemiol Infect, 2021 Full text Commentary |
Case-control | Delta | Adults aged 45 and up in a single centre in India | Any COVID-19 vaccine | ChAdOx1-S or BBV152 | No vaccine |
Serious Details |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|||||
| Inactivated virus | BBV152 | No vaccine |
Serious Details |
|||||
|
Skowronski DM, medRxiv, 2021 Full text Commentary Commentary |
Test-negative | Delta | SARS-CoV-2 test-positive cases and test-negative controls 18 years and over residing in British Columbia, Canada | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Heterologous | 1 ChAdOx-S + 1 BNT162b2 OR 1 mRNA-1273 | No vaccine |
Serious Details |
|||||
| Heterologous | 1 BNT162b2 + 1 mRNA-1273 | No vaccine |
Serious Details |
|||||
|
Skowronski DM, medRxiv, 2021 Full text Commentary Commentary |
Test-negative | Delta | SARS-CoV-2 test-positive cases and test-negative controls 18 years and over residing in Quebec, Canada | RNA based vaccine | mRNA-1273 | No vaccine |
Serious Details |
|
| Non replicating viral vector | ChAdOx1-S | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
| Heterologous | 1 ChAdOx-S + 1 BNT162b2 OR 1 mRNA-1273 | No vaccine |
Serious Details |
|||||
| Heterologous | 1 BNT162b2 + 1 mRNA-1273 | 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 |
|
| 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 |
|
| RNA based vaccine | BNT162b2 or mRNA-1273 | No vaccine |
Serious Details |
|||||
| RNA based vaccine | BNT162b2 | No vaccine |
Serious Details |
|||||
|
NCT04848584 Tartof S, Lancet, 2021 Full text (21)02183-8/fulltext; Full text Commentary 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 |
|
|
Tenforde M, MMWR, 2021 Full text Commentary |
Cohort | Delta | Hospitalized adults at 21 centers in the USA | RNA based vaccine | BNT162b2 or mRNA-1273 | No vaccine |
Serious Details |
|
|
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 |
|
|
Vaishya R, SSRN, 2021 Full text Commentary Commentary |
Cohort | Delta | Vaccinated healthcare workers in 43 hospitals in 24 Indian cities | Vaccine vs vaccine | ChAdOx1-S | BBV152 |
Serious Details |
|