Percorrer por autor "Braeye, Toon"
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- Comparison of two methods for the estimation of COVID-19 vaccine effectiveness of the autumnal booster within the VEBIS-EHR network in 2022/23Publication . Monge, Susana; Humphreys, James; Nicolay, Nathalie; Braeye, Toon; Van Evercooren, Izaak; Hansen, Christian Holm; Emborg, Hanne-Dorthe; Fabiani, Massimo; Sacco, Chiara; Castilla, Jesús; Martínez-Baz, Iván; de Gier, Brechje; Hahné, Susan; Hinta Meijerink; Kristoffersen, Anja Bråthen; Machado, Ausenda; Soares, Patricia; Fontán-Vela, Mario; Nardone, Anthony; Kissling, Esther; Nunes, Baltazar; VEBIS-Lot 4 working groupWithin an infrastructure to monitor vaccine effectiveness (VE) against hospitalization due to COVID-19 and COVID-19 related deaths from November 2022 to July 2023 in seven countries in real-world conditions (VEBIS network), we compared two approaches: (a) estimating VE of the first, second or third COVID-19 booster doses administered during the autumn of 2022, and (b) estimating VE of the autumn vaccination dose regardless of the number of prior doses (autumnal booster approach). Retrospective cohorts were constructed using Electronic Health Records at each participating site. Cox regressions with time-changing vaccination status were fit and site-specific estimates were combined using random-effects meta-analysis. VE estimates with both approaches were mostly similar, particularly shortly after the start of the vaccination campaign, and showed a similar timing of VE waning. However, autumnal booster estimates were more precise and showed a clearer trend, particularly compared to third booster estimates, as calendar time increased after the vaccination campaign and during periods of lower SARS-CoV-2 activity. Moreover, the decrease in protection by increasing calendar time was more clear and precise than when comparing protection by number of doses. Therefore, estimating VE under an autumnal booster framework emerges as a preferred method for future monitoring of COVID-19 vaccination campaigns.
- Effectiveness of JN.1 monovalent COVID-19 vaccination in EU/EEA countries between October 2024 and January 2025: a VEBIS electronic health record network studyPublication . Humphreys, James; Blake, Alexandre; Nicolay, Nathalie; Braeye, Toon; Van Evercooren, Izaak; Hansen, Christian Holm; Moustsen-Helms, Ida Rask; Sacco, Chiara; Mateo-Urdiales, Alberto; Castilla, Jesús; Martínez-Baz, Iván; Machado, Ausenda; Brito, André; Ljung, Rickard; Pihlstrom, Nicklas; Mansiaux, Yohann; Monge, Susana; Bacci, Sabrina; Nunes, Baltazar; VEBIS-Lot 4 working groupWe estimated vaccine effectiveness (VE) of Omicron JN.1-adapted COVID-19 vaccines administered during the 2024 autumnal vaccination campaign against COVID-19 hospitalisation and death among eligible individuals aged ≥65 years. The study period was October 2024-January 2025. Using a common protocol across six EU/EEA study sites, we linked electronic health records to construct retrospective cohorts and applied Cox modelling to estimate VE via confounder-adjusted hazard ratios. The majority of vaccines administered during the study period were Omicron JN.1-adapted COVID-19 vaccines (99 %). VE against hospitalisation was 60 % (95 % Confidence Interval: 48-70 %) and against COVID-19-related death was 78 % (95 %CI: 64-87 %) among individuals aged 65-79 years; 58 % (95 %CI: 48-66 %) and 62 % (95 %CI: 32-79 %) among those aged ≥80 years. These results indicate high effectiveness in the initial months of the campaign. Continued monitoring is necessary to confirm these results, including estimates of VE in those with longer time since vaccination and during different variant predominance periods.
- Effectiveness of the 2023 Autumn XBB.1.5 COVID-19 Booster During Summer 2024 in the EU/EEA: A VEBIS Electronic Health Record Network StudyPublication . Humphreys, James; Nicolay, Nathalie; Braeye, Toon; Van Evercooren, Izaak; Hansen, Christian Holm; Moustsen-Helms, Ida Rask; Sacco, Chiara; Fabiani, Massimo; Castilla, Jesús; Martinez-Baz, Ivan; Machado, Ausenda; Soares, Patricia; Ljung, Rickard; Pihlstrom, Nicklas; Kissling, Esther; Nardone, Anthony; Monge, Susana; Bacci, Sabrina; Nunes, Baltazar; VEBIS-EHR Working GroupBackground: After a period of low SARS- CoV-2 activity, viral circulation increased in Europe from May 2024, driven byimmune-evasive KP sublineages of the JN.1 variant. We estimated vaccine effectiveness (VE) of the XBB.1.5 dose administeredin 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 electronichealth records. VE against COVID-19-related hospitalisation and death during June–August 2024 was estimated using Cox re-gression 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 was13% (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.
- Effectiveness of XBB.1.5 Monovalent COVID‐19 Vaccines During a Period of XBB.1.5 Dominance in EU/EEA Countries, October to November 2023: A VEBIS‐EHR Network StudyPublication . Monge, Susana; Humphreys, James; Nicolay, Nathalie; Braeye, Toon; Van Evercooren, Izaak; Holm Hansen, Christian; Emborg, Hanne‐Dorthe; Sacco, Chiara; Mateo‐Urdiales, Alberto; Castilla, Jesús; Martínez‐Baz, Iván; de Gier, Brechje; Hahné, Susan; Meijerink, Hinta; Kristoffersen, Anja Bråthen; Machado, Ausenda; Soares, Patricia; Nardone, Anthony; Bacci, Sabrina; Kissling, Esther; Nunes, BaltazarUsing a common protocol across seven countries in the European Union/European Economic Area, we estimated XBB.1.5 monovalent vaccine effectiveness (VE) against COVID-19 hospitalisation and death in booster-eligible ≥ 65-year-olds, during October–November 2023. We linked electronic records to construct retrospective cohorts and used Cox models to estimate adjusted hazard ratios and derive VE. VE for COVID-19 hospitalisation and death was, respectively, 67% (95%CI: 58–74) and 67% (95%CI: 42–81) in 65- to 79-year-olds and 66% (95%CI: 57–73) and 72% (95%CI: 51–85) in ≥ 80-year-olds. Results indicate that periodic vaccination of individuals ≥ 65 years has an ongoing benefit and support current vaccination strategies in the EU/EEA.
- Excess all-cause mortality during the COVID-19 pandemic in Europe – preliminary pooled estimates from the EuroMOMO network, March to April 2020Publication . Vestergaard, Lasse S.; Nielsen, Jens; Richter, Lukas; Schmid, Daniela; Bustos, Natalia; Braeye, Toon; Denissov, Gleb; Veideman, Tatjana; Luomala, Oskari; Möttönen, Teemu; Fouillet, Anne; Caserio-Schönemann, Céline; an der Heiden, Matthias; Uphoff, Helmut; Lytras, Theodore; Gkolfinopoulou, Kassiani; Paldy, Anna; Domegan, Lisa; O'Donnell, Joan; de’ Donato, Francesca; Noccioli, Fiammetta; Hoffmann, Patrick; Velez, Telma; England, Kathleen; van Asten, Liselotte; White, Richard A.; Tønnessen, Ragnhild; Silva, Susana Pereira; Rodrigues, Ana Paula; Larrauri, Amparo; Delgado-Sanz, Concepción; Farah, Ahmed; Galanis, Ilias; Junker, Christoph; Perisa, Damir; Sinnathamby, Mary; Andrews, Nick; O'Doherty, Mark; Marquess, Diogo F.P.; Kennedy, Sharon; Olsen, Sonja J.; Pebody, Richard; Krause, Tyra G.; Mølbak, KåreA remarkable excess mortality has coincided with the COVID-19 pandemic in Europe. We present preliminary pooled estimates of all-cause mortality for 24 European countries/federal states participating in the European monitoring of excess mortality for public health action (EuroMOMO) network, for the period March–April 2020. Excess mortality particularly affected ≥ 65 year olds (91% of all excess deaths), but also 45–64 (8%) and 15–44 year olds (1%). No excess mortality was observed in 0–14 year olds.
- 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 2022Publication . 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 groupBackground: 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.
- Relative vaccine effectiveness against COVID-19 hospitalisation in persons aged ≥ 65 years: results from a VEBIS network, Europe, October 2021 to July 2023Publication . 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 groupSince 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.
- Unmeasured confounding and misclassification in studies estimating vaccine effectiveness against hospitalisation and death using electronic health records (EHRs): an evaluation of a multi-country European retrospective cohort studyPublication . Humphreys, James; Nicolay, Nathalie; Braeye, Toon; Van Evercooren, Izaak; Holm Hansen, Christian; Moustsen-Helms, Ida Rask; Sacco, Chiara; Mateo-Urdiales, Alberto; Castilla, Jesús; Martínez-Baz, Iván; Machado, Ausenda; Soares, Patricia; de Gier, Brechje; Meijerink, Hinta; Monge, Susana; Bacci, Sabrina; Nunes, Baltazar; VEBIS-EHR working groupBackground: Electronic health record (EHR)-based observational studies can rapidly provide real-world data on vaccine effectiveness (VE), though EHR data may be prone to misclassification and unmeasured confounding. Methods: In VEBIS-EHR, a retrospective multi-country COVID-19 VE cohort study, we examined unmeasured confounding using a negative control outcome (death not related to COVID-19) and misclassification due to timing of data extraction. The evaluation spanned two periods (November-December 2023, January-February 2024), encompassing up to 18.7 million individuals across six EU/EEA countries. Vaccine confounding-adjusted hazard ratios (aHRs) were pooled using random-effects meta-analysis. Results: aHRs against non-COVID-19 mortality ranged from 0.35 (95% CI: 0.28-0.44) to 0.70 (0.66-0.73) when comparing vaccinated versus unvaccinated. Delaying EHR data extraction modestly increased the capture of outcome and exposure events, with some variation by vaccination status. Site-level fluctuations in aHRs did not meaningfully alter the overall pooled VE, suggesting stable estimates despite misclassification related to extraction timing. Conclusions: We observed some evidence of unmeasured confounding when using non-COVID-19 deaths as a negative outcome, though the specificity of our negative control must be considered. This result may suggest overestimation of VE, but also the need for further analysis with more specific negative control outcomes and confounding-adjustment techniques. Addressing such confounding using richer data sources and more refined approaches remains critical to ensure accurate, timely VE estimates based on retrospective cohorts constructed using registry data. Extending the delay between the end of observation and data extraction modestly improves the completeness of exposure and outcome data, with limited effect on pooled VE estimates.