TY - JOUR
T1 - Effectiveness of messenger RNA vaccines against infection with SARS-CoV-2 during the periods of Delta and Omicron variant predominance in Japan
T2 - the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) study
AU - Mimura, Wataru
AU - Ishiguro, Chieko
AU - Maeda, Megumi
AU - Murata, Fumiko
AU - Fukuda, Haruhisa
N1 - Funding Information:
This research was supported by the Japan Agency for Medical Research and Development (AMED) under Grant Number JP21nf0101635. AMED played no role in the study design; the collection, analysis, and interpretation of data; the writing of the report; or the decision to submit the article for publication.
Publisher Copyright:
© 2022 The Author(s)
PY - 2022/12
Y1 - 2022/12
N2 - Objectives: We aimed to evaluate COVID-19 messenger RNA vaccine effectiveness during the Delta- and Omicron-predominant periods in Japan. Methods: We conducted a population-based cohort study among individuals aged 16–64 years during two periods: the Delta-predominant period (July 1–December 31, 2021) and the Omicron-predominant period (January 1–March 29, 2022). Results: When comparing individuals who were vaccinated with those who were unvaccinated, the effectiveness of a second dose against symptomatic infection was 89.8% (95% confidence interval [CI]: 80.5–94.7%) during the Delta-predominant period and 21.2% (95% CI: 11.0–30.3%) during the Omicron-predominant period. The effectiveness of a third dose against symptomatic infection was 71.8% (95% CI: 60.1–80.1%) during the Omicron-predominant period. Conclusion: Vaccine effectiveness against symptomatic infection decreased during the Omicron-predominant period but was maintained by a third dose.
AB - Objectives: We aimed to evaluate COVID-19 messenger RNA vaccine effectiveness during the Delta- and Omicron-predominant periods in Japan. Methods: We conducted a population-based cohort study among individuals aged 16–64 years during two periods: the Delta-predominant period (July 1–December 31, 2021) and the Omicron-predominant period (January 1–March 29, 2022). Results: When comparing individuals who were vaccinated with those who were unvaccinated, the effectiveness of a second dose against symptomatic infection was 89.8% (95% confidence interval [CI]: 80.5–94.7%) during the Delta-predominant period and 21.2% (95% CI: 11.0–30.3%) during the Omicron-predominant period. The effectiveness of a third dose against symptomatic infection was 71.8% (95% CI: 60.1–80.1%) during the Omicron-predominant period. Conclusion: Vaccine effectiveness against symptomatic infection decreased during the Omicron-predominant period but was maintained by a third dose.
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U2 - 10.1016/j.ijid.2022.10.001
DO - 10.1016/j.ijid.2022.10.001
M3 - Article
C2 - 36220547
AN - SCOPUS:85144589253
VL - 125
SP - 58
EP - 60
JO - International Journal of Infectious Diseases
JF - International Journal of Infectious Diseases
SN - 1201-9712
ER -
