A study published in Nature confirmed that older adults who received the shingles vaccine were 20% less likely to develop dementia over a seven‐year period compared with those who did not receive the shot. Researchers analyzed electronic health records for more than 280,000 elderly individuals in Wales, ages 79 to 88, who did not have dementia at the start of the national vaccination program. The vaccine, given as Zostavax—a first‐generation immunization that had been discontinued in the United States—was administered based on a strict age cutoff that formed two groups with nearly identical age, education, and health backgrounds except for vaccination status; those born on or after the cutoff date were eligible, while those born just before were not.
Shingles is a viral infection caused by the reactivation of the varicella‐zoster virus. One report noted that vaccination against herpes zoster in older adults might offer an unexpected benefit by reducing the risk of dementia. “It was a really surprising finding. This huge protective signal was there, no matter how you looked at the data,” said Pascal Geldsetzer, an assistant professor of medicine at Stanford University, according to a report by New York Post.
The study’s design, which relied on the arbitrary age cutoff to create comparable groups, revealed that vaccinated individuals experienced a 20% lower incidence of dementia over seven years—an absolute reduction of roughly 3.5 percentage points.
Researchers observed that the vaccine’s protective effect was more pronounced in women; female participants showed a greater reduction in dementia risk than their male counterparts. Some studies suggested that women mounted higher antibody responses than men, which might account for the observed gender difference.
Researchers acknowledged that the cause of the link between the shingles vaccine and reduced dementia risk remained unclear. One theory posited that the vaccine reduced inflammation in the nervous system by preventing the reactivation of latent virus, which may have helped guard against dementia development. The study’s robust design, comparing groups born only weeks apart, strengthened the hypothesis that vaccination against herpes zoster might offer benefits beyond the prevention of shingles.
Dementia affected more than 55 million people globally and was projected to impact one in three individuals over their lifetime. The findings contributed to a growing body of research investigating how interventions against common viral infections might influence the risk of neurodegenerative diseases, supporting the idea that herpes zoster reactivations—which could cause long‐lasting inflammation and nerve damage—were linked to cognitive decline and that vaccination may help reduce dementia incidence.
The article was written with the assistance of a news analysis system.