Observational studyBMC geriatrics2026
Effectiveness of seasonal influenza vaccine against dominant A(H1N1)pdm09 in adults ≥ 60 years: a multicenter test-negative design in Zhejiang, China, 2024-2025.
Observational study in BMC geriatrics, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
23 authors.
Funding
Abstract
backgroundZhejiang Province, China, has implemented a free influenza vaccination program for the elderly population for five consecutive years. However, data on real-world vaccine effectiveness against influenza among the local elderly population during the 2024-2025 influenza season are still lacking.
methodsA multicenter, retrospective test-negative design (TND) was adopted in this study. Sentinel surveillance networks were established across designated sentinel hospitals in six cities of Zhejiang Province, covering the period from October 2024 to July 2025. On a weekly basis, all or a systematic sample of patients aged ≥ 60 years presenting with influenza-like illness (ILI) were enrolled in the study. Epidemiological data were collected, respiratory specimens were obtained, and laboratory assays were conducted to detect influenza virus types and subtypes.
resultsOf the 4694 enrolled elderly patients with ILI, 1587 (33.81%) were influenza-positive, with A(H1N1)pdm09 being the dominant subtype (93.3%). Vaccination coverage was 32.72% (1536/4694). After adjusting for age, sex, chronic comorbidities, calendar week, and city, the overall VE was 53.3% (95% CI: 45.4-60.2). VE estimates by age group were 56.9% (95% CI: 45.8-65.8) for individuals aged 60-69 years, 51.2% (95% CI: 36.2-62.8) for 70-79 years, and 57.7% (95% CI: 37.2-71.8) for those aged ≥ 80 years. When compared with non-consecutive vaccination in the current season, VE for two, three, and four consecutive seasons was 44.6% (95% CI: 31.1-55.5), 35.5% (95% CI: 17.5-49.7), and 38.6% (95% CI: 18.8-53.6), respectively. Protection waned from 58.0% (95% CI: 37.6-71.7) within 59 days post-vaccination to 42.8% (95% CI: 33.4-50.9) between 60 and 180 days. Furthermore, vaccination provided effective protection against moderate-to-severe influenza (68.8%, 95% CI: 50.0-80.6) and influenza-associated hospitalization (53.9%, 95% CI: 37.3-66.0).
conclusionsIn the 2024-2025 season in Zhejiang, influenza vaccination offered moderate protection against laboratory-confirmed influenza among adults aged ≥ 60 years. While VE waned over time, consecutive vaccination maintained moderate effectiveness. The vaccine also provided substantial protection against moderate-to-severe influenza and hospitalization.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.