Overview
- The ECDC reports influenza activity in the European Economic Area is rising 3–4 weeks earlier than usual and urges immediate vaccination for people at higher risk and those with elevated exposure.
- A newly dominant A(H3N2) subclade (often labeled K or J.2.4.1) differs from the vaccine strain by multiple mutations, with the UK seeing early hospitalizations—especially among school-age children—while Germany has detected only sporadic cases so far.
- Early UK indicators suggest reduced adult protection from the seasonal vaccine against this variant (around 30–40%) with stronger protection against severe outcomes in children (about 70–75%).
- A Pfizer phase‑3 study published in the New England Journal of Medicine found its mRNA influenza vaccine prevented more cases than conventional shots (about 34.5% relative efficacy in adults 18–64) and generated stronger responses to A strains, with similar serious adverse event rates but more mild to moderate reactions.
- Moderna reports phase‑3 findings of at least non‑inferior or improved immune responses versus standard vaccines with increased side effects, and experts note mRNA platforms could enable later strain selection and faster production, though mRNA flu vaccines are still awaiting regulatory clearance and do not replace current options.