Effectiveness of first and second COVID-19 mRNA vaccine monovalent booster doses during a period of circulation of Omicron variant sublineages: December 2021-July 2022.
Influenza Other Respir Viruses
; 17(3): e13104, 2023 03.
Article
in English
| MEDLINE | ID: covidwho-2276322
ABSTRACT
Background:
US recommendations for COVID-19 vaccine boosters have expanded in terms of age groups covered and numbers of doses recommended, whereas evolution of Omicron sublineages raises questions about ongoing vaccine effectiveness.Methods:
We estimated effectiveness of monovalent COVID-19 mRNA booster vaccination versus two-dose primary series during a period of Omicron variant virus circulation in a community cohort with active illness surveillance. Hazard ratios comparing SARS-CoV-2 infection between booster versus primary series vaccinated individuals were estimated using Cox proportional hazards models with time-varying booster status. Models were adjusted for age and prior SARS-CoV-2 infection. The effectiveness of a second booster among adults ≥50 years of age was similarly estimated.Results:
The analysis included 883 participants ranging in age, from 5 to >90 years. Relative effectiveness was 51% (95% CI 34%, 64%) favoring the booster compared with primary series vaccination and did not vary by prior infection status. Relative effectiveness was 74% (95% CI 57%, 84%) at 15 to 90 days after booster receipt, but declined to 42% (95% CI 16%, 61%) after 91 to 180 days, and to 36% (95% CI 3%, 58%) after 180 days. The relative effectiveness of a second booster compared to a single booster was 24% (95% CI -40% to 61%).Conclusions:
An mRNA vaccine booster dose added significant protection against SARS-CoV-2 infection, but protection decreased over time. A second booster did not add significant protection for adults ≥50 years of age. Uptake of recommended bivalent boosters should be encouraged to increase protection against Omicron BA.4/BA.5 sublineages.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
COVID-19 Vaccines
/
COVID-19
Type of study:
Cohort study
/
Experimental Studies
/
Observational study
/
Prognostic study
/
Randomized controlled trials
Topics:
Vaccines
/
Variants
Limits:
Adult
/
Humans
Language:
English
Journal:
Influenza Other Respir Viruses
Journal subject:
Virology
Year:
2023
Document Type:
Article
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