How this page evolved

Every published version is kept. Each entry shows what changed and why. Earlier versions can be restored by moderators, but only if the material they rely on is still available.

1. Revision 3Oct 4, 2026, 3:57 PMLiveAI-organised, reviewed

   Adds newer evidence: pooled direct effectiveness of 44.1% versus indirect effectiveness of 13.7% under randomized conditions; 2024/25 Northern Ireland estimates including 46% overall, 60.8% in children, and waning over 2–16 weeks; age-group and pre/post-pandemic comparisons; and frailty-stratified results. Adds guidance on indirect protection, children, timing, and frailty, plus new open questions.

   • · The main finding was rewritten.
   • · Updated “How well do flu vaccines work overall?”.
   • · Updated “Older adults”.
   • · Added section “Children”.
   • · 4 new sources cited.
   • · The note on uncertainty changed.
   • · The key takeaways were revised.
   • · 2 new pieces of guidance for specific situations.
   • · 2 new open questions.
2. Revision 2Sep 30, 2026, 7:31 PMAI-organised, reviewed

   AI-prepared Starting Map from live research.

   • · First published version.