Study: Shingles Vaccine Shows Protective Effect Against Dementia

People with dementia who received a shingles vaccine have a significantly lower probability of dying from the disease compared to those who were unvaccinated, according to the results of a large-scale study cited by Reuters. The data, published in the journal Cell, suggest that the vaccine may slow the progression of dementia.

Of more than 14,000 older adults in Wales with established dementia at the start of the vaccination campaign, nearly half died from the disease within a nine-year follow-up period. However, for those who received Merck’s Zostavax vaccine, the risk of death due to dementia was nearly 30 percentage points lower.

Earlier this year, the same research team found that vaccinated adults were approximately 20% less likely to develop dementia at all compared to those who were unvaccinated.

“The most exciting aspect of the new results is that they suggest not only preventive and delaying effects on dementia, but also a potential therapeutic action in people who are already affected,” commented study lead Dr. Pascal Geldsetzer from Stanford University.

It remains unclear whether the vaccine’s protective effect is due to a general stimulation of the immune system, a reduction in the reactivation of the shingles virus, or another mechanism. It is also unknown whether GlaxoSmithKline’s newer Shingrix vaccine—which is more effective against shingles and contains only specific viral proteins—would have the same or a stronger effect on dementia.

As protection from the Merck vaccine wanes over time, it is no longer used in most countries since Shingrix proved to be more reliable. The researchers noted that over the past two years, they have confirmed the observations from Wales in health registries from England, Australia, New Zealand, and Canada.

“Time and again, we observe a strong protective effect against dementia across different databases,” says Dr. Geldsetzer.