Dataset Information

COVID-19 vaccine effectiveness against symptomatic SARS-CoV-2 infection during Delta-dominant and Omicron-dominant periods in Japan: a multi-center prospective case-control study (FASCINATE study).

ABSTRACT:

Background

Although several COVID-19 vaccines initially showed high efficacy, there have been concerns due to waning immunity and the emergence of variants with immune escape capacity.

Methods

A test-negative design case-control study was conducted in 16 healthcare facilities in Japan during the Delta-dominant period (August-September 2021) and the Omicron-dominant period (January-March 2022). Vaccine effectiveness (VE) against symptomatic SARS-CoV-2 infection was calculated for 2 doses for the Delta-dominant period and 2 or 3 doses for the Omicron-dominant period, compared to unvaccinated individuals.

Results

The analysis included 5795 individuals with 2595 (44.8%) cases. Among vaccinees, 2242 (55.8%) received BNT162b2 and 1624 (40.4%) received mRNA-1273 at manufacturer-recommended intervals. During the Delta-dominant period, VE was 88% (95% CI: 82-93) 14 days-3 months after dose 2 and 87% (95% CI: 38-97) 3-6 months after dose 2. During the Omicron-dominant period, VE was 56% (95% CI: 37-70) 14 days-3 months since dose 2, 52% (95% CI: 40-62) 3-6 months after dose 2, 49% (95% CI: 34-61) 6 + months after dose 2, and 74% (95% CI: 62-83) 14 + days after dose 3. Restricting to individuals at high risk of severe COVID-19 and additional adjustment for preventive measures (i.e. mask-wearing/high-risk behaviors) yielded similar estimates, respectively.

Conclusions

In Japan where most are infection-naïve and strict prevention measures are maintained regardless of vaccination status, 2-dose mRNA vaccines provided high protection against symptomatic infection during the Delta-dominant period and moderate protection during the Omicron-dominant period. Among individuals who received an mRNA booster dose, VE recovered to a high level.

SUBMITTER: Arashiro T

PROVIDER: S-EPMC9384625 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature

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Publications

Coronavirus Disease 19 (COVID-19) Vaccine Effectiveness Against Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection During Delta-Dominant and Omicron-Dominant Periods in Japan: A Multicenter Prospective Case-control Study (Factors Associated with SARS-CoV-2 Infection and the Effectiveness of COVID-19 Vaccines Study).

Arashiro Takeshi T Arashiro Takeshi T Arima Yuzo Y Muraoka Hirokazu H Sato Akihiro A Oba Kunihiro K Uehara Yuki Y Arioka Hiroko H Yanai Hideki H Kuramochi Jin J Ihara Genei G Chubachi Kumi K Yanagisawa Naoki N Nagura Yoshito Y Kato Yasuyuki Y Ueda Akihiro A Numata Akira A Kato Hideaki H Ishii Koji K Ooki Takao T Oka Hideaki H Nishida Yusuke Y Stucky Ashley A Smith Chris C Hibberd Martin M Ariyoshi Koya K Suzuki Motoi M

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 20230201 3

<h4>Background</h4>Although several coronavirus disease 2019 (COVID-19) vaccines initially showed high efficacy, there have been concerns because of waning immunity and the emergence of variants with immune escape capacity.<h4>Methods</h4>A test-negative design case-control study was conducted in 16 healthcare facilities in Japan during the Delta-dominant period (August-September 2021) and the Omicron-dominant period (January-March 2022). Vaccine effectiveness (VE) against symptomatic severe acu ...[more]

PMID: 35918782

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