Effectiveness of messenger RNA vaccines against infection with SARS-CoV-2 during the periods of Delta and Omicron variant predominance in Japan: the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) study.
Int J Infect Dis
; 125: 58-60, 2022 Oct 08.
Article
in English
| MEDLINE | ID: covidwho-2105081
ABSTRACT
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.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Type of study:
Cohort study
/
Experimental Studies
/
Observational study
/
Prognostic study
Topics:
Vaccines
/
Variants
Language:
English
Journal:
Int J Infect Dis
Journal subject:
Communicable Diseases
Year:
2022
Document Type:
Article
Affiliation country:
J.ijid.2022.10.001
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