Percorrer por autor "Moustsen-Helms, Ida Rask"
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- 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.
- 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.