Health Rounds: Study finds shingles vaccine decreases risk of dementia-related death

A recent study indicates that individuals with dementia who received a shingles vaccination had a notably reduced risk of dying from the condition compared to those who were not vaccinated. The research suggests that the vaccine may help slow the progression of dementia.

The study followed over 14,000 older adults in Wales who already had dementia at the start of the vaccination program. Nearly half of these participants died from dementia over a nine-year period. However, those who received Merck's Zostavax vaccine experienced an almost 30% lower risk of death from the disease, according to the report published in Cell.

Earlier research in Wales found that older adults who received the Zostavax vaccine were 20% less likely to develop dementia compared with peers who did not receive the vaccine. Dr. Pascal Geldsetzer of Stanford University, the study's lead author, highlighted that these findings suggest the shingles vaccine might not only help prevent dementia but could also have therapeutic effects for those already diagnosed.

The exact mechanism behind the protective effect remains unclear. Researchers are investigating whether the vaccine boosts the immune system generally, specifically reduces reactivation of the shingles virus, or works through another process entirely. It is also unknown if Shingrix, the newer shingles vaccine from GlaxoSmithKline, might offer similar or even stronger benefits against dementia, as it uses only viral proteins and is more effective at preventing shingles than Zostavax.

Researchers have replicated the Welsh findings using health records from countries including England, Australia, New Zealand, and Canada. Dr. Geldsetzer noted that this consistent protective effect across multiple datasets strengthens the evidence for a link between shingles vaccination and reduced dementia-related mortality.

Author: Maya Henderson