A vaccine that helps prevent the dreaded disease shingles may also have an effect on cognitive decline. In a new study published Thursday, scientists found that the latest shingles vaccine, Shingrex, is associated with a lower risk of dementia. However, more research will be needed to confirm causation and better understand how this effect occurs.
Herpes zoster Chickenpox is caused by the Varicella Zoster virus, the same bacteria that causes chickenpox in children and young people. Chickenpox is usually a short-lived but unpleasant illness, but the virus lies dormant in the nervous system, avoiding destruction by the body’s defense mechanisms. After decades, the virus can reappear and cause a new infection called shingles (about one-third of people with chickenpox eventually develop shingles). Shingles is often a frightening experience, causing intense pain, skin rash, and flu-like symptoms for up to five weeks. Some people suffer from lingering nerve pain that takes months or years to heal, while others may experience multiple bouts of shingles if they are unlucky.
Thankfully, a vaccine for shingles, Zostavax, has been available since 2006. Zostavax has since been replaced by the Shingrix vaccine (first approved in 2017), which is even more effective at preventing shingles, providing over 90% protection for at least seven years. Shingrix is also a recombinant vaccine, using parts of the target bacteria to induce immunity, whereas Zostavax uses a weakened version of the whole virus, meaning Shingrix can be used safely in immunocompromised individuals. As of 2020, only Shingrix is available in the United States and is recommended for almost everyone over the age of 50.
How to prevent dementia?
Several studies have been carried out over the years pointing There have been suggestions that the Zostavax vaccine may reduce the risk of dementia, but there has been relatively little research on Shingrix to date. Published In the journal Nature Medicine, That was exactly the purpose.
The researchers looked at the health records of more than 200,000 people who had been vaccinated against shingles in the United States, half of whom had received Shingrix. They found that over a six-year period, people who had received Shingrix were 17% less likely to develop dementia than people who had received the traditional Zostavax vaccine. They were also less likely to develop dementia than people who had received two other vaccines commonly used in older adults: the flu vaccine and the tetanus-diphtheria-pertussis vaccine (which served as a kind of control group). Even among people who did develop dementia, the researchers estimated that Shingrix vaccination delayed the onset of symptoms by about six months compared with Zostavax.
These studies alone do not prove that the Shingrix vaccine can prevent or slow the progression of dementia, and questions remain about how this prevention, if real, would work. was suggested For example, certain bacteria, including herpes viruses like chickenpox zoster, may directly cause dementia, but this link has also yet to be confirmed. At the very least, the scientists say their study should spur more definitive research investigating this link.
“These findings may stimulate research investigating the mechanisms underlying protection and facilitate the design of large randomized controlled trials to confirm the potential additional benefits of recombinant varicella zoster vaccines,” the researchers wrote in their paper.
