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Have any randomized clinical trials for the 2025–2026 influenza vaccine reported safety or efficacy results yet?
Executive summary
As of the reporting in the supplied sources, multiple randomized clinical trials of 2025-era influenza products have reported results: Moderna announced positive Phase 3 efficacy and immunogenicity data for its mRNA-1010 influenza vaccine in adults ≥50 (P304), and industry and journal reporting summarized that result and a modest relative efficacy (about 26.6% rVE) versus a standard vaccine [1] [2]. Large randomized trials of high‑dose influenza vaccines in older adults also reported benefits for hospitalization and lab‑confirmed influenza [3] [4]. Observational vaccine‑effectiveness surveillance from the Southern Hemisphere found about 50% protection against outpatient illness for the 2025 composition [5] [6]. Available sources do not mention randomized clinical trial safety/efficacy results for any other 2025–2026 branded influenza vaccines beyond those described above (not found in current reporting).
1. Moderna’s late‑stage readout: an mRNA flu vaccine registers modest efficacy
Moderna publicized P304 Phase 3 data showing its mRNA‑1010 influenza vaccine produced a stronger immune response and met efficacy goals in adults aged 50 and older; reporting gives a point estimate of roughly 26.6% relative efficacy versus a standard‑dose comparator and frames the result as “positive” and sufficient to support regulatory filings and development of a COVID–influenza combination product [1] [2]. Financial and trade press coverage emphasized immunogenicity and a consistent rVE signal across age and risk subgroups while noting company plans to pursue approvals and further analyses [1] [2].
2. Large randomized trials of high‑dose vaccines showed clinical benefit in older adults
Separate randomized trials — including large, individually randomized trials described in aggregate reporting — found high‑dose influenza formulations produced superior antibody responses and meaningful reductions in laboratory‑confirmed influenza and hospitalizations among adults ≥65, with prior trial data cited showing a 24% greater efficacy versus standard dose in multi‑season studies [3] [4]. The New England Journal of Medicine coverage and professional outlets presented these trial outcomes as supportive evidence for preferential use of high‑dose or adjuvanted products in older adults [3] [4].
3. Observational effectiveness data from the Southern Hemisphere adds context to trial signals
Public‑health surveillance and multi‑country observational analyses covering the 2025 Southern Hemisphere season reported adjusted vaccine effectiveness around 50.4% (95% CI 33.2–63.2) against outpatient influenza illness and roughly 49–50% against hospitalization, and authors and public‑health commentary treated these findings as consistent with the 2025–26 Northern Hemisphere vaccine composition and likely performance if similar viruses circulate [5] [6]. Those analyses are observational (not randomized trials) and measure real‑world effectiveness rather than randomized‑trial efficacy, but they provide independent, population‑level context for expected performance [5] [6].
4. Safety signals reported or absent in the cited trial reports
Moderna and the high‑dose trial summaries reported safety profiles consistent with prior expectations — Moderna reported predictable and “mild” safety signals and high‑dose vaccines were associated with expected reactogenicity but net benefit on hospitalizations — and none of the supplied summaries flagged novel or large safety concerns requiring immediate action [2] [3] [4]. If you seek more granular, adjudicated safety-event tables (serious adverse events, myocarditis, etc.), the supplied summaries do not include those line‑by‑line data; the NEJM review cited multiple vaccine safety tables for other vaccines but does not provide full datasets for each influenza trial in the excerpts provided [7].
5. What’s missing and how to interpret these results cautiously
The available sources provide company press releases, trade press, and surveillance/observational analyses; independent peer‑reviewed full datasets for some pivotal trials may be pending publication or embargo; industry summaries sometimes emphasize relative efficacy or immunogenicity without full subgroup or absolute risk data [1] [2]. The Southern Hemisphere VE numbers are observational and depend on circulating strains and study design; they are not randomized efficacy estimates and therefore can differ from trial results for population or subgroup effects [5] [6] [8]. Available sources do not mention randomized trial results for other 2025–2026 vaccine candidates beyond Moderna and the high‑dose trials (not found in current reporting).
6. Competing perspectives and the next steps for readers
Regulators and public‑health bodies (FDA, CDC, WHO, EMA) continue to publish composition recommendations and surveillance guidance for the 2025–26 season; those agencies emphasize vaccination despite variable VE estimates, and some reporting warns that changing circulating variants could reduce match and effectiveness [9] [10] [11]. Industry advocates highlight incremental gains from new platforms (mRNA) and higher‑dose formulations [1] [2] [3]; skeptics and some observational studies note seasons with low or even negative point estimates in select cohorts, reinforcing the need to interpret each study by design and population [12] [5]. For definitive trial safety and efficacy tables, consult forthcoming peer‑reviewed publications and regulatory filings cited by FDA/EMA and journal releases [2] [9].
If you want, I can track and summarize when peer‑reviewed publications or FDA/EMA briefing documents for Moderna’s P304 and the high‑dose trials appear, and extract detailed safety and subgroup efficacy tables from those primary sources.