Vaccine effectiveness against influenza hospitalisation in adults during the 2022/2023 mixed season of influenza A(H1N1)pdm09, A(H3N2) and B circulation, Europe: VEBIS SARI VE hospital network
Angela Rose, Francisco Pozo, Iván Martínez‐Baz, Clara Mazagatos, Nathalie Bossuyt, John Paul Cauchi, Goranka Petrović, Isabela Ioana Loghin, Roberta Vaikutytė, Silke Buda, Ausenda Machado, Róisín Duffy, Beatrix Oroszi, Jennifer Howard, Aitziber Echeverría, Cristina Andreu, Cyril Barbezange, Aušra Džiugytė, Diana Nonković, Corneliu‐Petru Popescu, Fausta Majauskaitė, Kristin Tolksdorf, Verónica Gomez, Lisa Domegan, J Horváth, Jesús Castilla, Miriam García, Thomas Demuyser, Maria‐Louise Borg, Irena Tabain, Mihaela Lazăr, Ieva Kubiliute, Ralf Dürrwald, Raquel Guiomar, Joan O’Donnell, Katalin Kristóf, Nathalie Nicolay, Sabrina Bacci, Esther Kissling, VEBIS SARI VE network team
Abstract
We conducted a multicentre hospital-based test-negative case-control study to measure vaccine effectiveness (VE) against PCR-confirmed influenza in adult patients with severe acute respiratory infection (SARI) during the 2022/2023 influenza season in Europe. Among 5547 SARI patients ≥18 years, 2963 (53%) were vaccinated against influenza. Overall VE against influenza A(H1N1)pdm09 was 11% (95% CI: -23-36); 20% (95% CI: -4-39) against A(H3N2) and 56% (95% CI: 22-75) against B. During the 2022/2023 season, while VE against hospitalisation with influenza B was >55%, it was ≤20% for influenza A subtypes. While influenza vaccination should be a priority for future seasons, improved vaccines against influenza are needed.