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. 2024 Jun 5;34(6):278-285.
doi: 10.2188/jea.JE20230106. Epub 2024 Jan 31.

Effectiveness of BNT162b2 Against Infection, Symptomatic Infection, and Hospitalization Among Older Adults Aged ≥65 Years During the Delta Variant Predominance in Japan: The VENUS Study

Wataru Mimura  1 , Chieko Ishiguro  1 , Junko Terada-Hirashima  2 , Nobuaki Matsunaga  3 , Shuntaro Sato  4 , Yurika Kawazoe  4 , Megumi Maeda  5 , Fumiko Murata  5 , Haruhisa Fukuda  5
Affiliations

Effectiveness of BNT162b2 Against Infection, Symptomatic Infection, and Hospitalization Among Older Adults Aged ≥65 Years During the Delta Variant Predominance in Japan: The VENUS Study

Wataru Mimura et al. J Epidemiol. .

Abstract

Background: We evaluated the effectiveness of the BNT162b2 vaccine against infection, symptomatic infection, and hospitalization in older people during the Delta-predominant period (July 1 to September 30, 2021).

Methods: We performed a population-based cohort study in an older adult population aged ≥65 years using data from the Vaccine Effectiveness, Networking, and Universal Safety Study conducted from January 1, 2019, to September 30, 2021, in Japan. We matched BNT162b2-vaccinated and -unvaccinated individuals in a 1:1 ratio on the date of vaccination of the vaccinated individual. We evaluated the effectiveness of the vaccine against infection, symptomatic infection, and coronavirus disease (COVID-19)-related hospitalization by comparing the vaccinated and unvaccinated groups. We estimated the risk ratio and risk difference using the Kaplan-Meier method with inverse probability weighting. The vaccine effectiveness was calculated as (1 - risk ratio) × 100%.

Results: The study included 203,574 matched pairs aged ≥65 years. At 7 days after the second dose, the vaccine effectiveness of BNT162b2 against infection, symptomatic infection, and hospitalization was 78.1% (95% confidence interval [CI], 65.2-87.8%), 79.1% (95% CI, 64.6-88.9%), and 93.5% (95% CI, 83.7-100%), respectively.

Conclusion: BNT162b2 was highly effective against infection, symptomatic infection, and hospitalization in Japan's older adult population aged ≥65 years during the Delta-predominant period.

Keywords: Delta variant; Japan; SARS-CoV-2 infection; cohort study; mRNA vaccine.

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Conflict of interest statement

Conflicts of interest: None declared.

Figures

Figure 1.
Figure 1.. Flow chart. COVID-19, coronavirus disease 2019.
Figure 2.
Figure 2.. Cumulative incidence of infection, symptomatic infection, and hospitalization after restricting the population at 7 days after the second dose
See this image and copyright information in PMC

References

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Publication types

Supplementary concepts