Interim estimates of 2018/19 vaccine effectiveness against influenza A(H1N1)pdm09, Canada, January 2019
Eurosurveillance·
- DOI
- 10.2807/1560-7917.es.2019.24.4.1900055
- PMID
- —
- PMCID
- —
- OpenAlex
- W2315196486
- Study type
- Journal article
- Publisher
- European Centre for Disease Control and Prevention (ECDC)
- Article type
- journal-article
- Integrity
- current
Why this research matters now
The findings document substantial seasonal influenza vaccine protection against the predominant circulating strain during the 2018/19 season, with particular relevance for young children who experienced disproportionate disease burden.
Structured evidence summary
Research question
The study assessed interim vaccine effectiveness against influenza A(H1N1)pdm09 during the 2018/19 season in Canada.
Study design
The investigation employed a test-negative design through the Canadian Sentinel Practitioner Surveillance Network. Sequence analysis was performed to characterize circulating viral variants.
Population and setting
The study enrolled patients presenting with medically attended influenza illness in Canada during January 2019. All age groups were included, with young children noted as disproportionately affected.
Main findings
Adjusted vaccine effectiveness against medically attended, laboratory-confirmed A(H1N1)pdm09 illness was 72% (95% CI: 60–81). Protection was substantial across all age groups. Sequence analysis revealed heterogeneity in emerging clade 6B.1 viruses without a dominant drift variant.
Public-health relevance
The findings document substantial seasonal influenza vaccine protection against the predominant circulating strain during the 2018/19 season, with particular relevance for young children who experienced disproportionate disease burden.
Important limitations
This summary relies on the supplied single-article abstract and metadata. The interim nature of the estimates and the scope of the test-negative design are noted, but comprehensive assessment of study limitations requires review of the original paper.
GIDS interpretation
The article is indexed under influenza surveillance and vaccine effectiveness topics for Canada, supporting discoverability in queries related to seasonal influenza vaccine performance and A(H1N1)pdm09 epidemiology during the 2018/19 season.
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 13 auditable classifier relationships to diseases, places, topics, and study design.