Effectiveness of mRNA COVID-19 vaccine booster doses against Omicron severe outcomes.
Nat Commun
; 14(1): 1273, 2023 03 07.
Article
in English
| MEDLINE | ID: covidwho-2261286
ABSTRACT
We estimated the effectiveness of booster doses of monovalent mRNA COVID-19 vaccines against Omicron-associated severe outcomes among adults in Ontario, Canada. We used a test-negative design to estimate vaccine effectiveness (VE) against hospitalization or death among SARS-CoV-2-tested adults aged ≥50 years from January 2 to October 1, 2022, stratified by age and time since vaccination. We also compared VE during BA.1/BA.2 and BA.4/BA.5 sublineage predominance. We included 11,160 cases and 62,880 tests for test-negative controls. Depending on the age group, compared to unvaccinated adults, VE was 91-98% 7-59 days after a third dose, waned to 76-87% after ≥240 days, was restored to 92-97% 7-59 days after a fourth dose, and waned to 86-89% after ≥120 days. VE was lower and declined faster during BA.4/BA.5 versus BA.1/BA.2 predominance, particularly after ≥120 days. Here we show that booster doses of monovalent mRNA COVID-19 vaccines restored strong protection against severe outcomes for at least 3 months after vaccination. Across the entire study period, protection declined slightly over time, but waned more during BA.4/BA.5 predominance.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
COVID-19
Type of study:
Experimental Studies
/
Observational study
Topics:
Vaccines
/
Variants
Limits:
Adult
/
Humans
Country/Region as subject:
North America
Language:
English
Journal:
Nat Commun
Journal subject:
Biology
/
Science
Year:
2023
Document Type:
Article
Affiliation country:
S41467-023-36566-1
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