Real-world Effectiveness of mRNA COVID-19 Vaccines Among US Nursing Home Residents Aged ≥65 Years in the Pre-Delta and High Delta Periods.
Open Forum Infect Dis
; 11(3): ofae051, 2024 Mar.
Article
em En
| MEDLINE
| ID: mdl-38505296
ABSTRACT
Background:
Long-term care residents were among the most vulnerable during the COVID-19 pandemic. We estimated vaccine effectiveness of mRNA COVID-19 vaccines in Medicare nursing home residents aged ≥65 years during pre-Delta and high Delta periods.Methods:
We conducted a retrospective cohort study from 13 December 2020 to 20 November 2021 using Medicare claims data. Exposures included 2 and 3 doses of Pfizer-BioNTech and Moderna COVID-19 vaccines. We used inverse probability weighting and Cox proportional hazards models to estimate absolute and relative vaccine effectiveness.Results:
Two-dose vaccine effectiveness against COVID-19-related death was 69.8% (95% CI, 65.9%â73.3%) during the pre-Delta period and 55.7% (49.5%â61.1%) during the high Delta period, without adjusting for time since vaccination. We observed substantial waning of effectiveness from 65.1% (54.2%â73.5%) within 6 months from second-dose vaccination to 45.2% (30.6%â56.7%) ≥6 months after second-dose vaccination in the high Delta period. Three doses provided 88.7% (73.5%â95.2%) vaccine effectiveness against death, and the incremental benefit of 3 vs 2 doses was 74.6% (40.4%â89.2%) during high Delta. Among beneficiaries with a prior COVID-19 infection, 3-dose vaccine effectiveness for preventing death was 78.6% (50.0%â90.8%), and the additional protection of 3 vs 2 doses was 70.0% (30.1%â87.1%) during high Delta. Vaccine effectiveness estimates against less severe outcomes (eg, infection) were lower.Conclusions:
This nationwide real-world study demonstrated that mRNA COVID-19 vaccines provided substantial protection against COVID-19-related death. Two-dose protection waned after 6 months. Third doses during the high Delta period provided significant additional protection for individuals with or without a prior COVID-19 infection.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Open Forum Infect Dis
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Estados Unidos