tetano
Editor, Senior Moderator
Clin Infect Dis
. 2022 Aug 3;ciac635.
doi: 10.1093/cid/ciac635. Online ahead of print.
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)
Takeshi Arashiro[SUP] 1 2 3 4 [/SUP], Yuzo Arima[SUP] 1 [/SUP], Hirokazu Muraoka[SUP] 5 [/SUP], Akihiro Sato[SUP] 6 [/SUP], Kunihiro Oba[SUP] 7 [/SUP], Yuki Uehara[SUP] 8 [/SUP], Hiroko Arioka[SUP] 9 [/SUP], Hideki Yanai[SUP] 10 [/SUP], Jin Kuramochi[SUP] 11 [/SUP], Genei Ihara[SUP] 12 [/SUP], Kumi Chubachi[SUP] 13 [/SUP], Naoki Yanagisawa[SUP] 14 [/SUP], Yoshito Nagura[SUP] 15 [/SUP], Yasuyuki Kato[SUP] 16 [/SUP], Akihiro Ueda[SUP] 17 [/SUP], Akira Numata[SUP] 18 [/SUP], Hideaki Kato[SUP] 19 [/SUP], Koji Ishii[SUP] 20 [/SUP], Takao Ooki[SUP] 20 [/SUP], Hideaki Oka[SUP] 21 [/SUP], Yusuke Nishida[SUP] 21 [/SUP], Ashley Stucky[SUP] 1 [/SUP], Chris Smith[SUP] 3 4 [/SUP], Martin Hibberd[SUP] 3 [/SUP], Koya Ariyoshi[SUP] 4 [/SUP], Motoi Suzuki[SUP] 1 [/SUP]
Affiliations
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.
Keywords: SARS-CoV-2 variants; coronavirus disease 2019 (COVID-19); severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); test-negative design; vaccine effectiveness.
. 2022 Aug 3;ciac635.
doi: 10.1093/cid/ciac635. Online ahead of print.
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)
Takeshi Arashiro[SUP] 1 2 3 4 [/SUP], Yuzo Arima[SUP] 1 [/SUP], Hirokazu Muraoka[SUP] 5 [/SUP], Akihiro Sato[SUP] 6 [/SUP], Kunihiro Oba[SUP] 7 [/SUP], Yuki Uehara[SUP] 8 [/SUP], Hiroko Arioka[SUP] 9 [/SUP], Hideki Yanai[SUP] 10 [/SUP], Jin Kuramochi[SUP] 11 [/SUP], Genei Ihara[SUP] 12 [/SUP], Kumi Chubachi[SUP] 13 [/SUP], Naoki Yanagisawa[SUP] 14 [/SUP], Yoshito Nagura[SUP] 15 [/SUP], Yasuyuki Kato[SUP] 16 [/SUP], Akihiro Ueda[SUP] 17 [/SUP], Akira Numata[SUP] 18 [/SUP], Hideaki Kato[SUP] 19 [/SUP], Koji Ishii[SUP] 20 [/SUP], Takao Ooki[SUP] 20 [/SUP], Hideaki Oka[SUP] 21 [/SUP], Yusuke Nishida[SUP] 21 [/SUP], Ashley Stucky[SUP] 1 [/SUP], Chris Smith[SUP] 3 4 [/SUP], Martin Hibberd[SUP] 3 [/SUP], Koya Ariyoshi[SUP] 4 [/SUP], Motoi Suzuki[SUP] 1 [/SUP]
Affiliations
- PMID: 35918782
- DOI: 10.1093/cid/ciac635
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.
Keywords: SARS-CoV-2 variants; coronavirus disease 2019 (COVID-19); severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); test-negative design; vaccine effectiveness.