A systematic meta-analytic comparative evaluation of seasonal influenza vaccine effectiveness from test-negative design studies in the Northern Hemisphere pre/post COVID-19 pandemic
Vaccine·
- DOI
- 10.1016/j.vaccine.2026.128956
- PMID
- 42486051
- PMCID
- —
- OpenAlex
- W7170036910
- Study type
- Systematic review
- Publisher
- Elsevier BV
- Article type
- journal-article
- Integrity
- current
Why this research matters now
The findings provide comparative context for interpreting seasonal influenza vaccine-effectiveness estimates across periods and age groups. The abstract indicates that factors other than population immunity could account for the observed differences, so the results do not establish a single explanation.
Structured evidence summary
Research question
The study evaluates whether pooled seasonal influenza vaccine-effectiveness estimates differed between pre-pandemic and post-pandemic periods in Northern Hemisphere test-negative studies.
Study design
This was a systematic review and meta-analysis of published peer-reviewed test-negative design studies. The analysis used inverse-variance random-effects models and compared pooled estimates across defined pre-pandemic and post-pandemic periods.
Population and setting
The evidence comprised 85 publications examining medically attended, laboratory-confirmed seasonal influenza in Northern Hemisphere settings. Estimates were grouped by influenza subtype and by ages 6 months–17 years, 18–64 years, and 65 years or older.
Main findings
Post-pandemic vaccine effectiveness against A(H3N2) was higher than pre-pandemic estimates among people aged 6 months–17 years and 18–64 years. Effectiveness against influenza B was also higher in those two age groups, while A(H1N1)pdm09 effectiveness was lower among 18–64-year-olds; no significant differences were reported for adults aged 65 years or older, and B/Victoria evidence was limited.
Public-health relevance
The findings provide comparative context for interpreting seasonal influenza vaccine-effectiveness estimates across periods and age groups. The abstract indicates that factors other than population immunity could account for the observed differences, so the results do not establish a single explanation.
Important limitations
The abstract identifies limited B/Victoria data and notes that factors other than population immunity may explain the observed differences. This summary is additionally limited to the supplied single-article abstract and metadata; the original paper is required for decision-grade assessment of study heterogeneity, bias, and analytic details.
GIDS interpretation
The article is discoverable as evidence concerning influenza vaccination and vaccine effectiveness, with COVID-19 appearing as a study-period context. It provides literature context only and does not confirm, measure, or explain any live surveillance signal.
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.