Percorrer por autor "Sacco, Chiara"
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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.
- COVID-19 vaccine effectiveness in the paediatric population aged 5-17 years: a multicentre cohort study using electronic health registries in six European countries, 2021 to 2022Publication . Soares, Patricia; Machado, Ausenda; Nicolay, Nathalie; Monge, Susana; Sacco, Chiara; Hansen, Christian Holm; Meijerink, Hinta; Martínez-Baz, Iván; Schmitz, Susanne; Humphreys, James; Fabiani, Massimo; Echeverria, Aitziber; AlKerwi, Ala'a; Nardone, Anthony; Mateo-Urdiales, Alberto; Castilla, Jesús; Kissling, Esther; Nunes, Baltazar; VEBIS-Lot 4 working groupBackground: During the first year of the COVID-19 pandemic, vaccination programmes targeted children and adolescents to prevent severe outcomes of SARS-CoV-2 infection. Aim: To estimate COVID-19 vaccine effectiveness (VE) against hospitalisation due to COVID-19 in the paediatric population, among those with and without previously documented SARS-CoV-2 infection. Methods: We established a fixed cohort followed for 12 months in Denmark, Norway, Italy, Luxembourg, Navarre (Spain) and Portugal using routine electronic health registries. The study commenced with paediatric COVID-19 vaccination campaign at each site between June 2021 and January 2022. The outcome was hospitalisation with a laboratory-confirmed SARS-CoV-2 infection or COVID-19 as the main diagnosis. Using Cox proportional hazard models, VE was estimated as 1 minus the confounder-adjusted hazard ratio of COVID-19 hospitalisation between vaccinated and unvaccinated. A random-effects meta-analysis was used to pool VE estimates. Results: We included 4,144,667 5-11-year-olds and 3,861,841 12-17-year-olds. In 12-17-year-olds without previous infection, overall VE was 69% (95% CI: 40 to 84). VE declined with time since vaccination from 77% ≤ 3 months to 48% 180-365 days after immunisation. VE was 94% (95% CI: 90 to 96), 56% (95% CI: 3 to 80) and 41% (95% CI: -14 to 69) in the Delta, Omicron BA.1/BA.2 and BA.4/BA.5 periods, respectively. In 12-17-year-olds with previous infection, one dose VE was 80% (95% CI: 18 to 95). VE estimates were similar for 5-11-year-olds but with lower precision. Conclusion: Vaccines recommended for 5-17-year-olds provided protection against COVID-19 hospitalisation, regardless of a previously documented infection of SARS-CoV-2, with high levels of protection in the first 3 months of the vaccination.
- 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.
- Estimated number of lives directly saved by COVID-19 vaccination programmes in the WHO European Region from December, 2020, to March, 2023: a retrospective surveillance studyPublication . Meslé, Margaux M.I.; Brown, Jeremy; Mook, Piers; Katz, Mark A.; Hagan, José; Pastore, Roberta; Benka, Bernhard; Redlberger-Fritz, Monika; Bossuyt, Nathalie; Stouten, Veerle; Vernemmen, Catharina; Constantinou, Elisabet; Maly, Marek; Kynčl, Jan; Sanca, Ondrej; Krause, Tyra Grove; Vestergaard, Lasse Skafte; Leino, Tuija; Poukka, Eero; Gkolfinopoulou, Kassiani; Mellou, Kassiani; Tsintziloni, Maria; Molnár, Zsuzsanna; Aspelund, Gudrun; Thordardottir, Marianna; Domegan, Lisa; Kelly, Eva; O'Donell, Joan; Urdiales, Alberto-Mateo; Riccardo, Flavia; Sacco, Chiara; Bumšteinas, Viktoras; Liausediene, Rasa; Mossong, Joël; Vergison, Anne; Borg, Maria-Louise; Melillo, Tanya; Kocinski, Dragan; Pollozhani, Enkela; Meijerink, Hinta; Costa, Diana; Gomes, João Paulo; Leite, Pedro Pinto; Druc, Alina; Gutu, Veaceslav; Mita, Valentin; Lazar, Mihaela; Popescu, Rodica; Popovici, Odette; Musilová, Monika; Mrzel, Maja; Socan, Maja; Učakar, Veronika; Limia, Aurora; Mazagatos, Clara; Olmedo, Carmen; Dabrera, Gavin; Kall, Meaghan; Sinnathamby, Mary; McGowan, Graham; McMenamin, Jim; Morrison, Kirsty; Nitzan, Dorit; Widdowson, Marc-Alain; Smallwood, Catherine; Pebody, Richard; WHO European Respiratory Surveillance NetworkBackground: By March, 2023, 54 countries, areas, and territories (hereafter CAT) in the WHO European Region had reported more than 2·2 million COVID-19-related deaths to the WHO Regional Office for Europe. Here, we estimated how many lives were directly saved by vaccinating adults in the WHO European Region from December, 2020, to March, 2023. Methods: In this retrospective surveillance study, we estimated the number of lives directly saved by age group, vaccine dose, and circulating variant-of-concern (VOC) period, regionally and nationally, using weekly data on COVID-19 mortality and infection, COVID-19 vaccination uptake, and SARS-CoV-2 virus characterisations by lineage downloaded from The European Surveillance System on June 11, 2023, as well as vaccine effectiveness data from the literature. We included data for six age groups (25-49 years, 50-59 years, ≥60 years, 60-69 years, 70-79 years, and ≥80 years). To be included in the analysis, CAT needed to have reported both COVID-19 vaccination and mortality data for at least one of the four older age groups. Only CAT that reported weekly data for both COVID-19 vaccination and mortality by age group for 90% of study weeks or more in the full study period were included. We calculated the percentage reduction in the number of expected and reported deaths. Findings: Between December, 2020, and March, 2023, in 34 of 54 CAT included in the analysis, COVID-19 vaccines reduced deaths by 59% overall (CAT range 17-82%), representing approximately 1·6 million lives saved (range 1·5-1·7 million) in those aged 25 years or older: 96% of lives saved were aged 60 years or older and 52% were aged 80 years or older; first boosters saved 51% of lives, and 60% were saved during the Omicron period. Interpretation: Over nearly 2·5 years, most lives saved by COVID-19 vaccination were in older adults by first booster dose and during the Omicron period, reinforcing the importance of up-to-date vaccination among the most at-risk individuals. Further modelling work should evaluate indirect effects of vaccination and public health and social measures.
- 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.