Jarvenpaa

Researchers are evaluating the effect of the recombinant zoster vaccine on the risk of being newly diagnosed with dementia in adults aged 76 years or older living in Finland. This Phase IV pragmatic trial compares the vaccine to a placebo to understand its impact on dementia incidence in an older adult population. Participants will be followed for up to 10 years to monitor the occurrence of dementia diagnoses, deaths, loss to follow-up, or the end of data availability. Participants are randomly assigned in a 3:1 ratio to receive either the recombinant zoster vaccine or a placebo. Both treatments are given as two intramuscular doses: the first dose at the initial visit (Day 1) and the second dose between 2 and 6 months after the first dose, following the approved dosing schedule. This setup allows researchers to observe and compare the long-term effects of the vaccine versus placebo on new dementia diagnoses. During the study, participants will be monitored through health register data to track dementia diagnosis and related health outcomes. The main measure is the hazard ratio for new dementia diagnoses from the first dose until the earliest of dementia diagnosis, death, loss to follow-up, or study end, with assessments continuing for up to 10 years. Participants must provide informed consent and remain living in the community, as those in nursing facilities are not eligible. Safety and adherence are overseen throughout the study period.