November 6, 2024
Could getting vaccinated against shingles also help to protect you against Alzheimer’s disease? New research suggests it might.
A third of Americans will eventually get shingles, or herpes zoster, a painful condition caused by the same virus that causes chickenpox. Most older Americans are infected with the chickenpox virus, even if we don’t remember having chickenpox as children. The virus lies dormant in nerve roots for decades and can be reactivated in later adulthood, causing the painful blisters of shingles. Shingles can affect the head, torso or other regions and, in addition to searing pain, lead to vision or hearing loss or potentially fatal brain inflammation.
That’s why the Centers for Disease Control and Prevention recommends that everyone age 50 and older get two doses of the Shingrix vaccine. The vaccine was approved for use in 2017, replacing an older type of shingles vaccine, and is highly effective in preventing or limiting damage from a shingles outbreak.
A new analysis has found that the shingles vaccine may have an added benefit: lowering the risk of Alzheimer’s disease and other forms of dementia.
Researchers at the University of Oxford studied electronic health records of more than 200,000 Americans over age 65. They found that getting the shingles vaccine significantly reduced the risk of developing dementia within six years after vaccination. For those eventually diagnosed with dementia, getting the Shingrix vaccine was linked to a 17 percent longer period of living free of dementia, compared to those who did not get the vaccine or who got other types of vaccines, such as the flu or tetanus vaccine. The Shingrix vaccine also appeared to be more protective against dementia than the earlier, less potent shingles vaccine. The findings were published in the journal Nature Medicine.
Other research has suggested links between shingles and dementia, though the evidence is mixed and inconclusive. Another recent study from researchers at Brigham and Women’s Hospital in Boston, for example, used data from three long-running studies of nurses and other health professionals. Nearly 150,000 men and women completed health status surveys every two years, including questions about shingles episodes and cognitive decline. The researchers found that men and women who had an outbreak of shingles had about a 20 percent higher risk of reporting thinking and memory problems over the long term than their peers who did not have shingles. The findings were published in the journal Alzheimer’s Research and Therapy.
Researchers aren’t sure why shingles might lead to cognitive decline. The chickenpox virus that causes shingles, varicella zoster, has been linked to an increased risk of heart disease and stroke, both risk factors for dementia. Some research suggests the virus may also damage the lining of blood vessels, including in the brain, or damage nerve cells directly. Infections may also increase brain inflammation, which may play a role in dementia onset; by limiting the severity of infections, vaccines may reduce brain inflammation.
Still, the idea that certain infections might contribute to the development of dementia, or that vaccination against certain infections might help to prevent dementia, remains controversial. The area is difficult to study because of variation in peoples’ habits. Vaccine recipients, for example, might in general be more health-conscious and therefore less likely to smoke, consume excess alcohol or be overweight, which are all recognized risk factors for dementia. More research is needed.
At the very least, it’s a good idea to get vaccinated against shingles if you are 50 or older. It can prevent a painful outbreak of shingles. And who knows? It may also help to keep your memory and thinking skills sharp for years to come.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, PhD, of The Fisher Center lab at The Rockefeller University.
Sources: Maxime Taquet, Quentin Dercon, John A. Todd, et al: “The recombinant shingles vaccine is associated with lower risk of dementia.” Nature Medicine, July 25, 2024
TS Yeh, G.C. Curhan, B.P. Yawn, et al: “Herpes zoster and long-term risk of subjective cognitive decline.” Alzheimer’s Research and Therapy, August 24, 2024
