2024/25 end-of-season KP.2 vaccine effectiveness against COVID-19 hospitalization in older adults: a test-negative study in Quebec, Canada
Vaccine·
- DOI
- 10.1016/j.vaccine.2026.128786
- PMID
- 42241837
- PMCID
- —
- OpenAlex
- W7163356532
- Study type
- Journal article
- Publisher
- Elsevier BV
- Article type
- journal-article
- Integrity
- current
Why this research matters now
The findings demonstrate that KP.2 vaccine provides meaningful but short-lived protection against COVID-19 hospitalization in older adults, informing vaccination timing and booster strategies for this vulnerable population.
Structured evidence summary
Research question
The study assessed the effectiveness of the 2024/25 KP.2 COVID-19 vaccine in preventing hospitalization among adults aged 60 years and older in Quebec, Canada.
Study design
Test-negative case-control design linking administrative records for vaccination, hospitalization, chronic disease, and laboratory data. The analysis adjusted for sex, age, comorbidities, residence, and epidemiological week.
Population and setting
Quebec residents aged 60 years and older who were eligible for publicly-funded COVID-19 vaccination and tested for COVID-19 in acute-care hospitals between October 2024 and August 2025. The study included 49,949 vaccinated participants (43% of the total cohort).
Main findings
Overall vaccine effectiveness against COVID-19 hospitalization was 34% over an analysis period of up to ten months, with median time since vaccination of 16 weeks. Protection declined from 43% in the first eight weeks post-vaccination to negligible by 32 weeks.
Public-health relevance
The findings demonstrate that KP.2 vaccine provides meaningful but short-lived protection against COVID-19 hospitalization in older adults, informing vaccination timing and booster strategies for this vulnerable population.
Important limitations
This summary is based on the supplied single-article abstract and metadata. Full interpretation of study limitations, including potential residual confounding, testing bias, and generalizability beyond Quebec, requires review of the complete published article.
GIDS interpretation
This peer-reviewed study from a Canadian jurisdiction provides vaccine effectiveness estimates for a recent COVID-19 vaccine formulation in older adults. The classifier links support discoverability under vaccination and vaccine effectiveness topics for COVID-19 in Canada.
Related GIDS surveillance
Literature context does not validate, explain, or change a surveillance signal. Exact and contextual relationships are shown separately.
Evidence relationships
This article has 11 auditable classifier relationships to diseases, places, topics, and study design.