Finland launches world’s first trial of shingles vaccine against dementia

Finland has launched the world’s first large randomised trial investigating whether a shingles vaccine can reduce the occurrence of memory disorders, Yle reports.

The FinDementia study will recruit more than 33,000 people aged 76 and over from across Finland. Three quarters of participants will randomly receive two doses of the shingles vaccine, while the remaining quarter will receive a placebo.

The study aims to establish whether shingles vaccination can help prevent memory disorders by influencing inflammatory reactions in the nervous system through the body’s immune system.

One participant, Pirjo Penttilä from Himanka, joined the study at the vaccine research clinic in Kokkola with her husband. Her husband, who is 81, was originally invited to take part, but the invitation was later extended to Penttilä after her husband’s appointment was postponed.

Penttilä said her main reason for joining was protection against shingles, although the possibility of protection against dementia was also interesting. Two doses of the vaccine cost more than 400 euros, which also influenced her decision.

The study uses the Shingrix vaccine, which has been available in the European Union since 2018 and has been given to more than 25 million people. It provides strong and long-lasting protection against shingles.

Observational data from the United States, England and Australia has shown a decline in dementia diagnoses after widespread shingles vaccination programmes began. The findings have been consistent and promising, but a causal link cannot be confirmed without a large randomised trial.

Arto Palmu, scientific director of the Finnish Vaccine Research organisation, said Finland’s comprehensive health registers would allow researchers to follow large groups over a long period.

The trial is blinded, meaning researchers and participants do not know which vaccine each person received. The study codes will be revealed only after the trial ends. Register-based monitoring will continue for at least three years, and the first results are expected in 2030.