The shingles vaccine can reduce the risk of dementia
New study
A new study concluded that the patients who received the shingles vaccine have a 20% lower risk of developing dementia.
Seven years of protection
The research, published in the journal Nature, found that the reduced risk lasts around seven years after receiving the vaccine.
Links between virus and brain decline
Experts told the New York Times and AP News that the results are the strongest evidence to date that some viral infections can affect brain functions years later.
Shingles
Shingles are caused by the same virus as chickenpox. The pathogen stays dormant inside the nerve cells of those who contracted the disease as children.
Reactivation
When the patient reaches a certain age or has a weakened immune system, the virus can reactivate, causing a painful blister rash that can last for weeks.
Painful and dangerous
Many people recover from shingles, but some develop chronic pain (the virus dwells in the nerves), and some can lose eyesight if the eye contracts the infection.
Possible links
For years, researchers have suspected pathogens like the chickenpox virus to have links to dementia because of neuroinflammation or the hits against the immune system.
Older studies
Older studies have found the same link between a reduced risk for dementia and the shingles vaccine, but they were unable to discard other factors that could be responsible.
Wales data
According to the New York Times, the new study used data from the 2013 Wales shingles vaccination rollout. Welsh officials established an age limit for the injection, with an exact date.
Natural experiment
The cut-off, at 79, provided a natural experiment for researchers. The vaccinated patients were only a week younger than those who did not meet the criteria.
Comparing similar groups
They analyzed the medical records of over 280,000 people between the ages of 71 and 88 when the rollout started and followed their health for years after. About half received the vaccine.
Discarding other factors
With that information, they compared both groups. They discarded any other factors that could affect dementia, like lifestyle or medication, that could increase the risk of Alzheimer's.
