The recombinant shingles vaccine is associated with lower risk of dementia.

There is emerging evidence that the live herpes zoster (shingles) vaccine might protect against dementia. However, the existing data are limited, and only refer to the live vaccine now discontinued in the USA and many other countries in favour of a recombinant vaccine. Whether the recombinant shingles vaccine protects against dementia remains unknown. Here we used a natural experiment opportunity created by the rapid transition from the use of live to the use of recombinant vaccines to compare the risk of dementia between vaccines. We show that the recombinant vaccine is associated with a significantly lower risk of dementia in the 6 years post-vaccination. Specifically, receiving the recombinant vaccine is associated with a 17% increase in diagnosis-free time, translating into 164 additional days lived without a diagnosis of dementia in those subsequently affected. The recombinant shingles vaccine was also associated with lower risks of dementia compared to two other vaccines commonly used in older people: influenza and tetanus/diphtheria/pertussis vaccines. The effect was robust across multiple secondary analyses, and present in both men and women but greater in women. These findings should stimulate studies investigating the mechanisms underpinning the protection and could facilitate the design of a large-scale randomised control trial to confirm the possible additional benefit of the recombinant shingles vaccine.