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

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Delta

Forest plots
(last update: 2021-10-28)

Description of primary studies

Trial Type Comparisons Design Participants Sample size Overall risk
of bias
Highest assessment
Full description
Intervention 1 Intervention 2
Alpha
Delta
NCT04641481
Bharat Biotech
Ella R(3), medRxiv, 2021

Full text
Commentary
Commentary
Inactivated virus

BBV152

Placebo

RCT
Phase 3
Adults with no history of SARS-CoV-2 infection who were healthy or had stable chronic medical conditions at 25 centers in India N=25778 Variant delta:

Some concerns
Details Variant alpha:

Some concerns
Details

Full description

Beta
Gamma
Delta
NCT04611243
Sinovac Research and Development Co., Ltd; and Pfizer/BioNTech + Fosun Pharma
Mok C K P, medRxiv, 2021

Full text
Commentary
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
Delta
NCT04762680
Sanofi Pasteur + GlaxoSmithKline
Sridhar S, medrxiv, 2021

Full text
Commentary
Commentary
Protein subunit

CoV2 preS dTM 15µg

CoV2 preS dTM 10µg

CoV2 preS dTM 5µg

RCT
Phase 2
Adults with and without prior SARS-CoV-2 infection and risk factors for severe disease at 20 centers in the USA and Honduras N=722
Low
Details

Full description