What peer‑reviewed, end‑of‑season meta‑analyses for Northern Hemisphere 2025–26 influenza vaccine effectiveness have been published since July 2025?
Executive summary
No peer‑reviewed, end‑of‑season meta‑analyses specifically assessing Northern Hemisphere 2025–26 influenza vaccine effectiveness published since July 2025 were identified in the provided reporting; available peer‑reviewed publications and surveillance reports through September–October 2025 are interim, regional, or early‑season assessments (not end‑of‑season meta‑analyses) and include the CDC/PAHO multi‑country Southern Hemisphere VE report (interim) and country‑level early analyses from England [1] [2] [3].
1. What the user is asking and why the record matters
The query targets a narrow publication type—peer‑reviewed, end‑of‑season meta‑analyses for the Northern Hemisphere 2025–26 season—meaning pooled, post‑season systematic syntheses published in journals after the season concluded; the assembled sources instead contain interim Southern Hemisphere VE surveillance (March–September 2025), early‑season characterization and preprints, and policy guidance, none of which meet that strict definition [1] [2] [4] [3].
2. What the provided sources actually contain (and why they are not the thing asked for)
The CDC/PAHO report summarized multi‑country, interim vaccine effectiveness from eight Southern Hemisphere countries for March–September 2025 and reported roughly 50% VE against outpatient visits and hospitalization, but it is an interim, regionally focused surveillance analysis rather than a post‑season meta‑analysis for the Northern Hemisphere 2025–26 season [2] [1] [5]; England’s early autumn analysis documented dominance of an H3N2 subclade (K/J.2.4.1) and reduced serologic reactivity to vaccine strains, but it is an early‑season characterization not a pooled, end‑of‑season VE meta‑analysis [3]. A medRxiv dashboard to support VE meta‑analyses exists as a preprint from June 2025, but it was posted before July 2025 and is not peer‑reviewed or a finalized NH 2025–26 end‑of‑season meta‑analysis [4].
3. Gaps, timing and typical publication cadence explain the absence
End‑of‑season meta‑analyses usually require complete national surveillance datasets, peer‑reviewed country studies, and time to perform systematic reviews and meta‑analytic pooling, so they commonly appear months after a season ends; given the 2025 Southern Hemisphere season data are interim through September 2025 and Northern Hemisphere activity was only beginning to be characterized in autumn 2025, the absence of peer‑reviewed NH 2025–26 end‑of‑season meta‑analyses in the supplied reporting is consistent with regular timelines for these syntheses [2] [3] [4].
4. Alternative sources and signals to watch (and their incentives)
Surveillance summaries and policy documents from WHO and FDA set vaccine composition and provide early signals about viral evolution and antigenic match—relevant but distinct from meta‑analyses—and both the WHO vaccine composition announcement and FDA strain recommendations were in the record [6] [7] [8]; public health agencies and clinical societies (e.g., ACP rapid practice points) synthesize evidence rapidly and may advocate for vaccination based on interim and prior meta‑analyses, an implicit public‑health agenda that favors uptake even before final pooled effectiveness estimates are available [9].
5. Bottom line and what credible next steps look like
Based on the provided reporting through autumn 2025, no peer‑reviewed, end‑of‑season meta‑analyses specifically for Northern Hemisphere 2025–26 influenza vaccine effectiveness published since July 2025 can be documented; the literature contains interim Southern Hemisphere VE estimates, early‑season country analyses, preprints and policy syntheses that will likely feed future meta‑analyses but do not substitute for a post‑season, peer‑reviewed pooled evaluation of NH 2025–26 [2] [1] [3] [4] [9].