Researchers who followed cases of dementia in adults in Welsh reveal the strongest evidence that shingles vaccinations reduce the risk of developing catastrophic brain disease.
Health records for more than 280,000 elderly people revealed that people who received the largely repealed shingles vaccine, known as Zostavax, are 20% less likely to be diagnosed with dementia in the next seven years.
Pascal Geldsetzer of Stanford University said: “For the first time, I can say with much more confidence that the shingles vaccine causes a lower risk of dementia.
Researchers took advantage of a vaccination rollout held in Wales more than a decade ago. Public Health Policy decided that from September 1, 2013, those born after September 2, 1933 became eligible for Zostavax shooting, but those older ones missed it.
This policy created a natural experiment in which older adults were sharply divided into two groups according to access to the vaccine. This allowed researchers to compare dementia rates among older adults a few weeks apart, on both sides of the vaccine eligibility gap.
After considering the fact that not everyone eligible for the vaccine received it, the researchers found it had the strongest impact in women, resulting in a 20% reduction in the risk of dementia. Anupam Ina, professor of healthcare policy at Harvard Medical School, said the impact was profound.
Dementia affects more than 55 million people worldwide and is the leading cause of death in the UK. One in three develops a disease in their lifetime, and drugs that slow the disease have recently been approved, but there is no cure.
When people infect chicken po, the virus remains dormant in nerve cells for life. However, the virus can reactivate and cause shingles in older people with weak immune systems and in people with weak immune systems.
The latest work, Published in Naturenot the first hint that the shingles vaccine could protect the shield against dementia. When Zostavax was deployed in the US in 2006, several studies found that dementia rates in people who received shots were low. Last year, researchers at Oxford reported even stronger protective effects on those who received the new vaccine, Singlix. Geldsetzer is currently looking for charities and private foundations to fund randomized clinical trials.
It is unclear how the shingles vaccine protects against dementia, but one theory is that it reduces inflammation in the nervous system by preventing virus reactivation. Another theory is that vaccines induce broader changes in the protective immune system. These broader effects are seen more frequently in women, potentially explaining gender differences in research.
In the attached article, Jena wrote: “It is still unknown that vaccinations for herpes zoster will reduce the risk of dementia, but the impact of the study is severe. The vaccine could represent a cost-effective intervention with public health benefits that are strongly beyond the intended purpose.”
Julia Dudley, head of research at Alzheimer’s Research UK, said the study strengthened the new link between shiny vaccination and lowering the risk of dementia. “While previous studies suggested a connection, this study provides stronger evidence of direct linking and greater benefits are observed in women.
“It is unclear exactly how the shingles vaccine will affect the risk of dementia, which could reduce inflammation, protect the brain, and support the immune system with other mechanisms.
“A better understanding of this link, including reasons for the differences between men and women, could open up new avenues for the prevention and treatment of dementia,” she said.
Maxim Toke, who found a lower risk of dementia after receiving the Singrix vaccine, said adjuvants for vaccines that make the immune response stronger could play a role. Both studies “strongly support the hypothesis that shingles vaccinations reduce the risk of dementia, and new recombinant vaccines provide excellent protection,” he said. “The key question is whether this enhanced protection is due to improved prevention of shingles or the immunological effects of adjuvants.”
