Antunes, LilianaMazagatos, ClaraMartínez-Baz, IvánGómez, VerónicaBorg, Maria-LouisePetrović, GorankaDuffy, RóisínDufrasne, François EDürrwald, RalfLazar, MihaelaJancoriene, LigitaOroszi, BeatrixHusa, PetrHoward, JenniferMelo, ArysePozo, FranciscoPérez-Gimeno, GloriaCastilla, JesúsMachado, AusendaDžiugytė, AušraKarabuva, SvjetlanaFitzgerald, MargaretFierens, SébastienTolksdorf, KristinPopovici, Silvia-OdetteMickienė, AuksėTúri, GergőSoučková, LenkaNicolay, NathalieRose, Angela MCon behalf of the European Hospital Vaccine Effectiveness Group2024-01-222024-01-222024-01-18Euro Surveill. 2024 Jan;29(3):2300708. doi: 10.2807/1560-7917.ES.2024.29.3.23007081025-496Xhttp://hdl.handle.net/10400.18/8934Members of the European Hospital Vaccine Effectiveness Group: Portugal: Ana Paula Rodrigues, Débora Pereira, Susana Costa Maia e Silva, Paula Pinto, Cristina Bárbara, António Pais de Lacerda, Raquel Guiomar and Camila Henriques.The European Medicines Agency (EMA) authorised four adapted bivalent mRNA COVID-19 vaccines for use against COVID-19 in September/October 2022: Comirnaty (BNT162b2; Pfizer-BioNTech) and Spikevax (mRNA-1273; Moderna) Original/Omicron BA.1 and Original/Omicron BA.4–5 [1]. During autumn 2022, all European Union/European Economic Area (EU/EEA) countries had vaccination campaigns in place to administer a booster dose, with several countries using the adapted bivalent vaccines [2]. The Omicron-descendent XBB lineage and XBB.1.5 sub-lineage became variants of interest in March 2023 [3]. We estimated the effectiveness of the COVID-19 bivalent vaccines against hospitalisation with PCR-confirmed SARS-CoV-2 infection among patients aged ≥ 60 years with severe acute respiratory infection (SARI) during the XBB lineage-predominant period.engCOVID-19COVID-19 Bivalent VaccinesHospitalisationSARIXBBVEBIS-LOT 1SARS-CoV-2Vaccine EffectivenessEuropeVacinaEfetividadeObservação e vigilânciaInfecções RespiratóriasCuidados de Saúdejournal article10.2807/1560-7917.ES.2024.29.3.2300708