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Influenza Other Respir Viruses
. 2025 Dec;19(12):e70198.
doi: 10.1111/irv.70198. Effectiveness of the 2023 Autumn XBB.1.5 COVID-19 Booster During Summer 2024 in the EU/EEA: A VEBIS Electronic Health Record Network Study
James Humphreys 1 , Nathalie Nicolay 2 , Toon Braeye 3 , Izaak Van Evercooren 3 , Christian Holm Hansen 4 , Ida Rask Moustsen-Helms 4 , Chiara Sacco 5 6 , Massimo Fabiani 5 , Jesús Castilla 7 8 , Iván Martínez-Baz 7 8 , Ausenda Machado 9 , Patricia Soares 9 , Rickard Ljung 10 11 , Nicklas Pihlström 10 11 , Esther Kissling 1 , Anthony Nardone 1 , Susana Monge 12 13 , Sabrina Bacci 2 , Baltazar Nunes 1 ; VEBIS‐EHR working group
Collaborators, Affiliations
Background: After a period of low SARS-CoV-2 activity, viral circulation increased in Europe from May 2024, driven by immune-evasive KP sublineages of the JN.1 variant. We estimated vaccine effectiveness (VE) of the XBB.1.5 dose administered in autumn 2023 against COVID-19-related hospitalisations and deaths in individuals 65 years of age or older during this period.
Methods: We conducted a multi-country cohort study across six EU nations in the VEBIS-EHR network using linked electronic health records. VE against COVID-19-related hospitalisation and death during June-August 2024 was estimated using Cox regression in a two-stage analysis, adjusting for demographics, comorbidities and prior vaccination history.
Results: Among individuals 65-79 and ≥ 80 years old, respectively, VE of the XBB.1.5 dose ≥ 6 months post administration was 13% (95% CI: -12% to 33%) and 7% (95% CI: -7% to 19%) against hospitalisation and 39% (95% CI: -7% to 65%) and 3% (95% CI: -23% to 23%) against deaths.
Conclusions: XBB.1.5 vaccination provided minimal residual protection against severe COVID-19 outcomes among adults aged ≥ 65 years more than 6 months after vaccination, during the summer 2024 period of increased SARS-CoV-2 activity.
Keywords: COVID‐19; XBB.1.5; electronic health records; vaccine effectiveness.
. 2025 Dec;19(12):e70198.
doi: 10.1111/irv.70198. Effectiveness of the 2023 Autumn XBB.1.5 COVID-19 Booster During Summer 2024 in the EU/EEA: A VEBIS Electronic Health Record Network Study
James Humphreys 1 , Nathalie Nicolay 2 , Toon Braeye 3 , Izaak Van Evercooren 3 , Christian Holm Hansen 4 , Ida Rask Moustsen-Helms 4 , Chiara Sacco 5 6 , Massimo Fabiani 5 , Jesús Castilla 7 8 , Iván Martínez-Baz 7 8 , Ausenda Machado 9 , Patricia Soares 9 , Rickard Ljung 10 11 , Nicklas Pihlström 10 11 , Esther Kissling 1 , Anthony Nardone 1 , Susana Monge 12 13 , Sabrina Bacci 2 , Baltazar Nunes 1 ; VEBIS‐EHR working group
Collaborators, Affiliations
- PMID: 41312816
- DOI: 10.1111/irv.70198
Background: After a period of low SARS-CoV-2 activity, viral circulation increased in Europe from May 2024, driven by immune-evasive KP sublineages of the JN.1 variant. We estimated vaccine effectiveness (VE) of the XBB.1.5 dose administered in autumn 2023 against COVID-19-related hospitalisations and deaths in individuals 65 years of age or older during this period.
Methods: We conducted a multi-country cohort study across six EU nations in the VEBIS-EHR network using linked electronic health records. VE against COVID-19-related hospitalisation and death during June-August 2024 was estimated using Cox regression in a two-stage analysis, adjusting for demographics, comorbidities and prior vaccination history.
Results: Among individuals 65-79 and ≥ 80 years old, respectively, VE of the XBB.1.5 dose ≥ 6 months post administration was 13% (95% CI: -12% to 33%) and 7% (95% CI: -7% to 19%) against hospitalisation and 39% (95% CI: -7% to 65%) and 3% (95% CI: -23% to 23%) against deaths.
Conclusions: XBB.1.5 vaccination provided minimal residual protection against severe COVID-19 outcomes among adults aged ≥ 65 years more than 6 months after vaccination, during the summer 2024 period of increased SARS-CoV-2 activity.
Keywords: COVID‐19; XBB.1.5; electronic health records; vaccine effectiveness.