Vaccine effectiveness against influenza hospitalisation in adults during
the 2022/23 mixed season of influenza A(H1N1)pdm09, A(H3N2) and B
circulation, Europe: VEBIS SARI VE hospital network
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 2022/23 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 2022/23 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 the
upcoming season, improved vaccines against influenza are needed.
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