Getting a vaccine shot for shingles could lower the risk of dementia by 20%, with women likely to have relatively better protection than men, a new research has suggested.
The latest finding provides the strongest evidence yet that the shingles jab helps reduce cognitive decline .
The study published in Nature has given further credence to an emerging theory that viruses that affect the nervous system can increase the risk of developing dementia.
The researchers studied health records of more than 280,000 older adults and found that those who were jabbed with a largely discontinued shingles vaccine called Zostavax were 20% less likely to be diagnosed with dementia over the next seven years compared to those who didn't get vaccinated.
“For the first time we are able to say much more confidently that the shingles vaccine causes a reduction in dementia risk. If this truly is a causal effect, we have a finding that’s of tremendous importance," said Pascal Geldsetzer, at Stanford University.
How Shingles virus is reactivated
Shingles cases emerge from the same virus that causes childhood chickenpox, and varicella-zoster. It typically hides and remains dormant in nerve cells for decades. With age and weakened immune system, the virus can reactivate and cause shingles. Symptoms include burning, tingling, painful blisters and numbness. The nerve pain can become chronic and disabling.
In the US, about one in three people will develop shingles in their lifetime, with roughly a third of eligible adults receiving the vaccine, according to the CDC.
How the researchers made the discovery
The researchers capitalized on a vaccination rollout in Wales that began over a decade ago. Starting on September 1, 2013, public health policy made individuals born on or after September 2, 1933, eligible for the Zostavax vaccine, while those born earlier were excluded.
This helped the researchers divide the older population into two groups based on their vaccine eligibility. This allowed them to compare dementia rates among people born just weeks apart, with one group having access to the vaccine and the other not.
After adjusting for the fact that not all eligible individuals received the vaccine, the study found that vaccination resulted in a 20% reduction in dementia risk, with the most significant effect observed in women.
Dementia is a broad term for a decline in mental ability severe enough to interfere with daily life. It affects memory, thinking, and reasoning, often leading to confusion and difficulty with tasks. Alzheimer's disease is the most common cause, but dementia can result from various conditions, including stroke and Parkinson's disease.
It affects more than 55 million people globally. While drugs that slow the disease have recently been approved, there is no cure to dementia as yet.
How shingles vaccines guard against dementia
While it's not clear yet, but there is one theory suggesting that they reduce inflammation in the nervous system by preventing reactivation of the virus. Another theory says the vaccines induce broader changes in the immune system that are protective. These effects are noticed more often in women, which explains the sex differences in the study.
“It’s unclear exactly how the shingles vaccine might influence dementia risk. It may reduce inflammation, support the immune system in ways that protect the brain or involve other mechanisms. It’s important to note that this study looked at the Zostavax vaccine rather than Shingrix, which is now more commonly used.
“Understanding this link better, including the reason for any differences between men and women, could open new avenues for dementia prevention and treatment,” Julia Dudley, the head of research at Alzheimer’s Research UK, said.
The latest finding provides the strongest evidence yet that the shingles jab helps reduce cognitive decline .
The study published in Nature has given further credence to an emerging theory that viruses that affect the nervous system can increase the risk of developing dementia.
The researchers studied health records of more than 280,000 older adults and found that those who were jabbed with a largely discontinued shingles vaccine called Zostavax were 20% less likely to be diagnosed with dementia over the next seven years compared to those who didn't get vaccinated.
“For the first time we are able to say much more confidently that the shingles vaccine causes a reduction in dementia risk. If this truly is a causal effect, we have a finding that’s of tremendous importance," said Pascal Geldsetzer, at Stanford University.
How Shingles virus is reactivated
Shingles cases emerge from the same virus that causes childhood chickenpox, and varicella-zoster. It typically hides and remains dormant in nerve cells for decades. With age and weakened immune system, the virus can reactivate and cause shingles. Symptoms include burning, tingling, painful blisters and numbness. The nerve pain can become chronic and disabling.
In the US, about one in three people will develop shingles in their lifetime, with roughly a third of eligible adults receiving the vaccine, according to the CDC.
How the researchers made the discovery
The researchers capitalized on a vaccination rollout in Wales that began over a decade ago. Starting on September 1, 2013, public health policy made individuals born on or after September 2, 1933, eligible for the Zostavax vaccine, while those born earlier were excluded.
This helped the researchers divide the older population into two groups based on their vaccine eligibility. This allowed them to compare dementia rates among people born just weeks apart, with one group having access to the vaccine and the other not.
After adjusting for the fact that not all eligible individuals received the vaccine, the study found that vaccination resulted in a 20% reduction in dementia risk, with the most significant effect observed in women.
Dementia is a broad term for a decline in mental ability severe enough to interfere with daily life. It affects memory, thinking, and reasoning, often leading to confusion and difficulty with tasks. Alzheimer's disease is the most common cause, but dementia can result from various conditions, including stroke and Parkinson's disease.
It affects more than 55 million people globally. While drugs that slow the disease have recently been approved, there is no cure to dementia as yet.
How shingles vaccines guard against dementia
While it's not clear yet, but there is one theory suggesting that they reduce inflammation in the nervous system by preventing reactivation of the virus. Another theory says the vaccines induce broader changes in the immune system that are protective. These effects are noticed more often in women, which explains the sex differences in the study.
“It’s unclear exactly how the shingles vaccine might influence dementia risk. It may reduce inflammation, support the immune system in ways that protect the brain or involve other mechanisms. It’s important to note that this study looked at the Zostavax vaccine rather than Shingrix, which is now more commonly used.
“Understanding this link better, including the reason for any differences between men and women, could open new avenues for dementia prevention and treatment,” Julia Dudley, the head of research at Alzheimer’s Research UK, said.
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