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Browsing by Author "Van Evercooren, Izaak"

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  • Monitoring COVID‐19 vaccine effectiveness against COVID‐19 hospitalisation and death using electronic health registries in ≥65 years old population in six European countries, October 2021 to November 2022
    Publication . Kislaya, Irina; Sentís, Alexis; Starrfelt, Jostein; Nunes, Baltazar; Martínez‐Baz, Iván; Nielsen, Katrine Finderup; AlKerwi, Ala'a; Braeye, Toon; Fontán‐Vela, Mario; Bacci, Sabrina; Meijerink, Hinta; Castilla, Jesús; Emborg, Hanne‐Dorthe; Hansen, Christian Holm; Schmitz, Susanne; Van Evercooren, Izaak; Valenciano, Marta; Nardone, Anthony; Nicolay, Nathalie; Monge, Susana; VEBIS‐Lot4 working group
    Background: Within the ECDC-VEBIS project, we prospectively monitored vaccine effectiveness (VE) against COVID-19 hospitalisation and COVID-19-related death using electronic health registries (EHR), between October 2021 and November 2022, in community-dwelling residents aged 65-79 and ≥80 years in six European countries. Methods: EHR linkage was used to construct population cohorts in Belgium, Denmark, Luxembourg, Navarre (Spain), Norway and Portugal. Using a common protocol, for each outcome, VE was estimated monthly over 8-week follow-up periods, allowing 1 month-lag for data consolidation. Cox proportional-hazards models were used to estimate adjusted hazard ratios (aHR) and VE = (1 - aHR) × 100%. Site-specific estimates were pooled using random-effects meta-analysis. Results: For ≥80 years, considering unvaccinated as the reference, VE against COVID-19 hospitalisation decreased from 66.9% (95% CI: 60.1; 72.6) to 36.1% (95% CI: -27.3; 67.9) for the primary vaccination and from 95.6% (95% CI: 88.0; 98.4) to 67.7% (95% CI: 45.9; 80.8) for the first booster. Similar trends were observed for 65-79 years. The second booster VE against hospitalisation ranged between 82.0% (95% CI: 75.9; 87.0) and 83.9% (95% CI: 77.7; 88.4) for the ≥80 years and between 39.3% (95% CI: -3.9; 64.5) and 80.6% (95% CI: 67.2; 88.5) for 65-79 years. The first booster VE against COVID-19-related death declined over time for both age groups, while the second booster VE against death remained above 80% for the ≥80 years. Conclusions: Successive vaccine boosters played a relevant role in maintaining protection against COVID-19 hospitalisation and death, in the context of decreasing VE over time. Multicountry data from EHR facilitate robust near-real-time VE monitoring in the EU/EEA and support public health decision-making.
    2023-11-28Journal article Open access Show more
  • Relative vaccine effectiveness against COVID-19 hospitalisation in persons aged ≥ 65 years: results from a VEBIS network, Europe, October 2021 to July 2023
    Publication . Fontán-Vela, Mario; Kissling, Esther; Nicolay, Nathalie; Braeye, Toon; Van Evercooren, Izaak; Holm Hansen, Christian; Emborg, Hanne-Dorthe; Fabiani, Massimo; Mateo-Urdiales, Alberto; AlKerwi, Ala'a; Schmitz, Susanne; Castilla, Jesús; Martínez-Baz, Iván; de Gier, Brechje; Hahné, Susan; Meijerink, Hinta; Starrfelt, Jostein; Nunes, Baltazar; Caetano, Constantino; Derrough, Tarik; Nardone, Anthony; Monge, Susana; VEBIS-Lot 4 working group
    Since 2021, the Vaccine Effectiveness, Burden and Impact Studies of coronavirus disease 2019 (COVID-19) and influenza (VEBIS) project monitors vaccine effectiveness (VE) in real-world conditions to inform vaccination programmes in the European Union/European Economic Area (EU/EEA) countries [1]. One project aims to monitor real-time COVID-19 VE using electronic health registries (EHR) in multiple countries, with initial findings previously published [2-4]. We report pooled VE results against hospitalisation due to COVID-19 by number of doses received and time since vaccination in a community-dwelling resident population aged ≥ 65 years between October 2021 and July 2023.
    2024-01Journal article Open access Show more