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Meta-Analysis
. 2022 May;94(5):2269-2274.
doi: 10.1002/jmv.27568. Epub 2022 Jan 18.

The effectiveness of mRNA-1273 vaccine against COVID-19 caused by Delta variant: A systematic review and meta-analysis

Chia S Kow  1   2 , Dinesh S Ramachandram  2 , Syed S Hasan  3   4
Affiliations
Meta-Analysis

The effectiveness of mRNA-1273 vaccine against COVID-19 caused by Delta variant: A systematic review and meta-analysis

Chia S Kow et al. J Med Virol. 2022 May.

Abstract

We aimed to perform meta-analyses to summarize the overall effectiveness of the mRNA-1273 vaccine against COVID-19 caused by the Delta variant from real-world studies. A systematic literature search with no language restriction was performed in electronic databases to identify eligible observational studies that reported the effectiveness of the mRNA-1273 vaccine to prevent reverse transcription-polymerase chain reaction (RT-PCR) confirmed COVID-19 caused by Delta variant of SARS-CoV-2 (B.1.617.2). A random-effects meta-analysis model was used to estimate the pooled odds ratio (OR) at a 95% confidence interval (CI), and the vaccine effectiveness was indicated as (pooled OR - 1)/OR. Five studies were included for this systematic review and meta-analysis. The meta-analysis revealed that the administration of mRNA-1273 vaccine protected against RT-PCR confirmed COVID-19 caused by Delta variant ≥21 days post first dose, with pooled vaccine effectiveness of 66% (95% CI: 65%-67%), as well as ≥14 days after the second dose, with pooled vaccine effectiveness of 91% (95% CI: 84%-95%). In conclusion, the mRNA-1273 vaccine offers a substantial protection rate against RT-PCR confirmed COVID-19 caused by the Delta variant upon full vaccination, although with slightly reduced effectiveness relative to other strains of SARS-CoV-2.

Keywords: coronavirus; disease control; pathogenesis; respiratory tract; vaccines/vaccine strains; virus classification.

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Conflict of interest statement

The authors declare that there are no conflict of interests.

Figures

Figure 1
Figure 1
PRISMA flow diagram for study selection
Figure 2
Figure 2
Pooled odds ratio (OR) of the incidence of COVID‐19 caused by Delta variant 21 days after the first dose of vaccine (A) and 14 days after the second dose of vaccine (B) relative to no vaccination
See this image and copyright information in PMC

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