A recent study published in the journal Nature suggests a potential link between the shingles vaccine and a reduced risk of developing dementia. To investigate this correlation, the researchers analyzed data from a population of Welsh individuals residing in the United Kingdom. Adults born after September 2, 1933, were eligible for a free vaccination, whereas those born before that date were not. Nearly half of the eligible individuals received the vaccine, compared to a negligible number that missed the cutoff date.

The researchers compared the dementia diagnosis rates of the two groups and found that the vaccinated subjects were 20 percent less likely to develop dementia in the subsequent seven years as compared to the unvaccinated group. Notably, the protective effect was more pronounced in women than in men. Hypothesizing why the shingles vaccine had this effect, the study’s senior author, Dr. Pascal Geldsetzer, told The New York Times, “Inflammation is a bad thing for many chronic diseases, including dementia, [so] reducing these reactivations and the accompanying inflammation may have benefits for dementia.”

The shingles virus, which is caused by the same virus responsible for chickenpox, can remain dormant in nerve cells for decades before reactivating in older adults as their immune systems weaken. Symptoms include burning and tingling sensations, painful blisters and numbness, and may also lead to chronic nerve pain. According to the U.S. Centers for Disease Control and Prevention, approximately one in three Americans will develop the condition in their lifetime, but only about one-third of adults over the age of 50 have been vaccinated.