{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T21:34:41Z","timestamp":1791840881608,"version":"4.3.4"},"reference-count":43,"publisher":"Oxford University Press (OUP)","issue":"8","license":[{"start":{"date-parts":[[2026,8,23]],"date-time":"2026-08-23T00:00:00Z","timestamp":1787443200000},"content-version":"vor","delay-in-days":22,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,8,3]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Older adults in nursing homes face high influenza-related morbidity and mortality due to immunosenescence and comorbidities, which may reduce vaccine effectiveness. High-dose (HD) influenza vaccine, containing four times more antigen than standard-dose (SD) formulations, aim to compensate for this impaired immune response.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To compare the Relative Vaccine Effectiveness (rVE) of HD versus SD influenza vaccines against influenza-related hospitalisations (primary), and hospitalisations due to pneumonia or combined influenza\/pneumonia (secondary) in nursing home residents aged \u226565\u00a0years.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Study Design<\/jats:title>\n                    <jats:p>Nationwide retrospective cohort (French SNDS). Residents vaccinated between 1 September 2022, and 31 March 2023, were followed until 30 June 2023, discharge or death. Facilities with in-house pharmacies were excluded.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Exposures\/Outcomes<\/jats:title>\n                    <jats:p>HD vs. SD influenza vaccine (pharmacy dispensing codes). Hospitalisations identified by ICD-10 discharge codes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>HD and SD recipients were matched 1:1 using propensity scores with exact matching on sex, age group, region and vaccination week. Incidence rate ratios (IRR) were estimated using Poisson\/negative binomial models. rVE\u2009=\u2009(1\u2013IRR)\u2009\u00d7\u2009100.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Among 315\u00a0239 residents (123\u00a0720 HD; 191\u00a0519 SD), 76\u00a0858 pairs were matched (mean age 88\u00a0years; 75% women). Influenza hospitalisation rates were 302 vs. 438 per 100\u00a0000 person-years, corresponding to an rVE of 30.8% (95% CI: 11.8\u201345.7; P\u2009=\u2009.0029). No significant rVE was observed for pneumonia or combined outcomes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions and Relevance<\/jats:title>\n                    <jats:p>HD vaccine was associated with a significant reduction in influenza-related hospitalisations in French nursing home residents, supporting preferential HD use in this high-risk population. Residual confounding cannot be excluded, and vaccine safety was not assessed in the present analysis.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/ageing\/afag238","type":"journal-article","created":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T11:17:53Z","timestamp":1786101473000},"source":"Crossref","is-referenced-by-count":2,"title":["Comparative effectiveness of high-dose versus standard-dose influenza vaccines in nursing home residents aged 65 and older in France: a nationwide cohort study on the French health data system from the 2022\u20132023 season"],"prefix":"10.1093","volume":"55","author":[{"given":"Helene","family":"Bricout","sequence":"first","affiliation":[{"name":"Medical Department, Sanofi Pasteur SA , Lyon, Auvergne-Rh\u00f4ne-Alpes ,","place":["France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marie-Cecile","family":"Levant","sequence":"additional","affiliation":[{"name":"Medical Department, Sanofi Pasteur SA , Lyon, 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