COVID-19 vaccine effectiveness on variants of concern
(Randomized evidence)

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Gamma

Forest plots
(last update: 2022-04-15)

Description of primary studies

Trial Type Comparisons Design Participants Sample size Overall risk
of bias
Highest assessment
Full description
Intervention 1 Intervention 2
Gamma
Delta
NCT04672395
Clover Biopharmaceuticals Inc./Dynavax
Bravo L, Lancet, 2022

Full text
Commentary
Commentary
Protein subunit

SCB-2019

Placebo

RCT
Phase 2-3
Healthy adults or with stable chronic conditions, both SARS-CoV-2 seropositive and seronegative, at 31 centers in Belgium, Brazil, Colombia, Philippines, and South Africa. N=30174 Variant delta:

Some concerns
Details

Full description

Beta
Gamma
Delta
ChiCTR2100051998
Sinovac Research and Development Co. Ltd.; Anhui Zhifei Longcom Biopharmaceutical + Institute of Microbiology, Chinese Academy of Sciences
Cao Y, Cell Res, 2021

Full text
Commentary
Inactivated virus

CoronaVac/Boost ZF2001

CoronaVac/Boost CoronaVac

RCT
Phase 2
Healthcare professionals with no previous confirmed COVID-19 at a single center in China who had received two doses of CoronaVac in a 28-day interval 4–8 months earlier N=164
Some concerns
Details

Full description

Gamma
ISRCTN89951424
AstraZeneca+University of Oxford
Clemens S, Nat. Commun., 2021

Full text
Commentary
Commentary
Non replicating viral vector

ChAdOx1

MenACWY

RCT
Phase 3
Adults that were SARS-CoV-2 seronegative and with no history of COVID-19 in six centers in Brazil. N=10416 Variant gamma:

Some concerns
Details

Full description

Alpha
Gamma
Delta
NCT04646590
Anhui Zhifei Longcom Biopharmaceutical
Dai L, N Engl J Med, 2022

Full text
Commentary
Commentary
Protein subunit

ZF2001

Placebo

RCT
Phase 3
Adults 18 years of age or older with no history of Covid-19, positive tests for SARS-CoV-2 exposure or vaccination, or of congenital or acquired immune deficiency or autoimmune disease at 32 clinical centers across Uzbekistan, Indonesia, Pakistan, Ecuador and China. N=28904 Variant delta:

Some concerns
Details

Full description

Alpha
Beta
Gamma
Delta
NCT04636697
Medicago Inc
Hager K, N Engl J Med, 2022

Full text
Full text
Commentary
Virus-Like particle

CoVLP

Placebo

RCT
Phase 3
Adults including elderly with and without comorbidities, with no previous history of virologically confirmed COVID-19, both seronegative and seropositive, at 85 centers in Argentina, Brazil, Canada, Mexico, the UK, and the USA. N=24141 Variant delta:

Some concerns
Details

Full description

Alpha
Beta
Gamma
Delta
NCT04614948
Janssen Pharmaceutical Companies
Hardt K, medRxiv, 2022
ENSEMBLE2

Full text
Commentary
Commentary
Non replicating viral vector

Ad26.COV2.S Ad26.COV2.S

Placebo

RCT
Phase 3
Adults, healthy or with stable and well-controlled comorbidities, at 125 centers in Belgium, Brazil, Colombia, France, Germany, The Philippines, South Africa, Spain, UK, and USA N=31835
Some concerns
Details

Full description

Alpha
Gamma
NCT04652102; EudraCT 2020-003998-22
CureVac AG
Kremsner P, Lancet Infect Dis, 2022
HERALD

Full text
Commentary
RNA based vaccine

CVnCoV

Placebo

RCT
Phase 2-3
Adults with no history of COVID-19 in 47 centers in Belgium, Germany, The Netherlands, Spain, Argentina, Colombia, Dominican Republic, Mexico, Panama and Peru N=39680
Some concerns
Details

Full description

Beta
Gamma
Delta
NCT04611243
Sinovac/Pfizer/BioNTech+Fosun Pharma
Mok C K P, Am. J. Respir. Crit., 2022

Full text
Commentary
Inactivated virus

CoronaVac/Boost

CoronaVac/Boost BNT162b2

RCT
*
Adults that had received two doses of CoronaVac but had low immune response against SARS-CoV-2 at two centres in Hong Kong, China N=80
Some concerns
Details

Full description

Beta
Gamma
NCT04764422
The Government Pharmaceutical Organization (GPO); PATH; Dynavax
Pitisuttithum P, medRxiv, 2021

Full text
Commentary
Commentary
Inactivated virus

NDV-HXP-S 1mcg

NDV-HXP-S 1mcg + CpG1018

NDV-HXP-S 3mcg

NDV-HXP-S 3mcg + CpG1018

NDV-HXP-S 10mcg

NDV-HXP-S 1mcg

Placebo

RCT
Phase 1
Healthy adults without immunosuppression negative for SARS-CoV-2 antibodies at a single center in Thailand N=210
Some concerns
Details

Full description

Alpha
Beta
Gamma
Delta
NCT05142319
Pfizer/BioNTech+Fosun Pharma; ModernaTX
Poh XY, Clin. Infect. Dis., 2022
PRIBIVAC

Full text
Commentary
RNA based vaccine

BNT162b2/boostm1273

BNT162b2/boostBNT

RCT
3
Adults at a single center in Singapore with no previous history of COVID-19 who had received a primary series of BTN162b2 at least 6 months previously N=100
Some concerns
Details

Full description

Alpha
Beta
Gamma
NCT04505722
Janssen Pharmaceutical Companies
Sadoff J, N Engl J Med, 2022
ENSEMBLE

Full text
Commentary
Non replicating viral vector

Ad26.COV2.S

Placebo

RCT
Phase 3
Adults >18 years of age at 213 centers in Argentina, Brazil, Chile, Colombia, Mexico, Peru, South Africa and USA N=44325 Variant beta:

Some concerns
Details

Full description