What are the CDC estimates for 2025-2026 H3N2 vaccine effectiveness by age group?

1. What CDC actually posts about 2025–2026 VE — the record on file

The CDC’s 2025–2026 season landing pages summarize vaccine composition, recommendations for all people ≥6 months, and supply projections, but they do not present published, age‑specific H3N2 VE percentages for 2025–2026 in those pages referenced in the search results ^{[4] [5]}. Available CDC seasonal summaries linked in the results discuss virus circulation and vaccine composition but do not contain the UK‑style interim VE breakdown by age group ^[6].

2. Where the commonly quoted 72–75% (children) and 30–40% (adults) numbers come from

Initial, real‑world VE estimates for the early 2025–26 season come from a UK Health Security Agency preprint and interim report that were widely reported. Those documents and media coverage report VE against emergency‑department visits and hospital attendance of roughly 72–75% in children and adolescents under 18 and approximately 32–39% (commonly rounded to 30–40%) in adults ^{[3] [2] [1]}. U.S. outlets (CIDRAP, Patient Care Online) and specialist outlets are citing these UK figures as early indicators for the Northern Hemisphere season ^{[1] [2]}.

3. Why CDC might not mirror UK VE estimates immediately

CDC typically produces its own VE estimates using U.S. surveillance systems (FluView, FluSurv‑NET, test‑negative studies) and will publish interim VE when domestic data accumulate; the CDC season pages emphasize surveillance and composition but do not replace or re‑publish foreign interim VE estimates ^{[4] [6]}. The reporting shows U.S. surveillance early in the season indicating rising H3N2 circulation, but CDC’s documents in the provided results do not yet present U.S. age‑stratified VE numbers for 2025–26 ^{[6] [4]}.

4. How journalists and clinicians are using UK interim VE — strengths and limits

Clinicians and commentators are treating UK interim VE as an early signal because the UK dataset is large and timely; outlets report it as evidence the 2025–26 vaccine still protects substantially in children and offers modest protection in adults ^{[2] [1]}. Limitations are explicit in those reports: the UK figures are interim, based on early circulating strains (subclade K in the UK), and may not translate exactly to U.S. experience because of differences in circulating viruses, vaccine formulations (egg‑based vs. cell/recombinant), population immunity, and timing ^{[3] [6]}.

5. Competing viewpoints and implicit agendas to watch

Coverage splits between voices urging rapid vaccination (arguing any protection reduces severe outcomes) and those warning of a potential mismatch that could lower effectiveness later in the season; both positions appear in the sources ^{[7] [2]}. Some reporting emphasizes vaccine supply and CDC recommendations to vaccinate everyone ≥6 months (a public‑health advocacy stance consistent with CDC guidance), while other analysts stress surveillance gaps and warn that early VE could change as the season evolves ^{[4] [1]}.

6. Bottom line and what to watch next

If you want U.S. CDC‑issued, age‑specific VE values for 2025–26, current CDC pages cited here do not provide them; the best available early numeric estimates are from UK interim analyses reporting ~72–75% VE in children (2–17) and ~30–40% in adults, which U.S. outlets quote ^{[3] [1] [2]}. Monitor CDC surveillance updates (FluView/FluSurv‑NET and CDC VE publications) for U.S. interim VE and for any divergence from the UK figures as domestic case data accumulate ^{[4] [6]}.

Limitations: this analysis uses only the documents and reporting supplied in the search results; available sources do not mention a CDC‑published, age‑stratified H3N2 VE table for 2025–2026 in the linked CDC pages ^{[4] [5]}.