Effectiveness of high-dose #influenza #vaccine against #hospitalisations in older #adults (FLUNITY-HD): an individual-level pooled analysis
Summary Background Two large-scale trials comparing high-dose inactivated influenza vaccine (HD-IIV) versus standard-dose inactivated influenza vaccine (SD-IIV) against hospitalisation outcomes have been conducted in Denmark and Spain . We aimed to analyse the pooled data from these trials to enhance generalisability and assess the relative vaccine effectiveness (rVE) of HD-IIV versus SD-IIV against severe clinical outcomes in older adults. Methods FLUNITY-HD was a prespecified, individual-level pooled analysis of two methodologically harmonised pragmatic, individually randomised trials comparing HD-IIV with SD-IIV in older adults. DANFLU-2 included adults aged 65 years or older and GALFLU included community-dwelling adults aged 65–79 years. DANFLU-2 was conducted during the 2022–23, 2023–24, and 2024–25 influenza seasons in Denmark, whereas GALFLU was conducted during the 2023–24 and 2024–25 seasons in Galicia, Spain. In both trials, participants were randomly assigned (1:1) to ...