Influenza A viruses circulated in Europe from September 2023 to January 2024, with influenza A(H1N1)pdm09 predominance. We provide interim 2023/24 influenza vaccine effectiveness (IVE) estimates from two European studies, covering 10 countries across primary care (EU-PC) and hospital (EU-H) settings. Interim IVE was higher against A(H1N1)pdm09 than A(H3N2): EU-PC influenza A(H1N1)pdm09 IVE was 53% (95% CI: 41 to 63) and 30% (95% CI: -3 to 54) against influenza A(H3N2). For EU-H, these were 44% (95% CI: 30 to 55) and 14% (95% CI: -32 to 43), respectively.

• MeSH
• chřipka lidská * epidemiologie   prevence a kontrola   MeSH
• lidé MeSH
• nemocnice MeSH
• primární zdravotní péče MeSH
• roční období MeSH
• studie případů a kontrol MeSH
• vakcinace MeSH
• vakcíny proti chřipce * MeSH
• virus chřipky A, podtyp H1N1 * MeSH
• virus chřipky A, podtyp H3N2 MeSH
• virus chřipky B MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

We conducted a multicentre hospital-based test-negative case-control study to measure the effectiveness of adapted bivalent COVID-19 mRNA vaccines against PCR-confirmed SARS-CoV-2 infection during the Omicron XBB lineage-predominant period in patients aged ≥ 60 years with severe acute respiratory infection from five countries in Europe. Bivalent vaccines provided short-term additional protection compared with those vaccinated > 6 months before the campaign: from 80% (95% CI: 50 to 94) for 14-89 days post-vaccination, 15% (95% CI: -12 to 35) at 90-179 days, and lower to no effect thereafter.

• MeSH
• COVID-19 * prevence a kontrola   MeSH
• hospitalizace MeSH
• lidé MeSH
• messenger RNA MeSH
• SARS-CoV-2 genetika   MeSH
• studie případů a kontrol MeSH
• vakcíny proti COVID-19 * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH