Shingles Vaccine Shows Promise in Dementia Research
A shingles vaccination program introduced in Wales back in 2013 has uncovered two significant findings that may help in the fight against dementia. It seems that the vaccine not only lowers the chances of developing mild cognitive impairment but also appears to slow down the progression of dementia in individuals who are already diagnosed.
Earlier reports highlighted the potential of the vaccine in preventing dementia, following a study published in Nature. Now, a follow-up study has found that vaccinated individuals with existing dementia diagnoses show fewer cases of death attributable to the condition.
The latest research, conducted by an international team, contributes to an increasing body of evidence suggesting that halting viruses affecting the nervous system—like the varicella zoster virus, which causes shingles—might also offer protection against dementia.
“Considering that the vaccine is safe, affordable, and readily available, this discovery could have significant public health implications,” says Haroon Ahmed, an epidemiologist at Cardiff University in the UK. He emphasizes that more research is needed to explore the potential protective effects of the vaccine against dementia, particularly to understand its mechanisms.
The vaccination program in Wales, initiated over a decade ago by the UK National Health Service, provided an unusual chance to analyze a kind of randomized clinical trial without formal implementation: individuals aged 79 were eligible for the vaccine, while those who were 80 could not be vaccinated. This peculiar setup offered researchers a way to examine the effects in two closely matched groups, minimizing the influence of other dementia risk factors like education or other medical conditions.
Of 14,350 people diagnosed with dementia before the program began, nearly half passed away due to the illness within nine years. However, those vaccinated against shingles had nearly a 30% lower chance of this outcome, indicating a substantial level of protection.
The study also revealed that participants who received the vaccine were less likely to develop mild cognitive impairment, which often precedes dementia. When combined with previous findings indicating that the vaccine reduces the risk of developing dementia in the first place, this paints an encouraging picture.
Pascal Geldsetzer, a biomedical scientist at Stanford University, finds the results particularly exciting, noting that they imply the shingles vaccine may not just offer preventive benefits against dementia but could also provide therapeutic benefits for those already affected.
While the unique design of the Welsh vaccination effort lends some weight to the findings, the current data doesn’t firmly establish a direct cause and effect. Still, the strong correlation suggests further investigation is warranted.
Future research will likely need to clarify why the shingles vaccine has this potential effect on dementia development and diagnosis. There could be mechanisms related to the nervous or immune systems at play; for instance, viruses affecting the nervous system have been linked to toxic protein accumulations seen in Alzheimer’s, as suggested by animal models.
Further studies might involve larger participant pools across a broader age range while investigating the new vaccine that has replaced the one used in Wales in 2013.
“Investing some resources in exploring these pathways could lead to breakthroughs in treatment and prevention,” Geldsetzer concludes.
The findings are detailed in research published in Cell.
