Professor of Epidemiology at Harvard University
A study published in Nature magazine analysed the medical records of elderly Welsh men and women and discovered that those who had been vaccinated against shingles were 20% less likely to develop dementia in the following seven years. This effect was greater in women. The findings support the theory that viruses that affect the nervous system can increase the risk of dementia.
An international team of scientists, led by Stanford University (United States), has designed a study to analyse the relationship between herpes zoster virus infections and the development of dementia. To do so, they took advantage of the introduction of the Zostavax vaccine against this virus in 2013 in Wales (UK), which people over the age of 80 could not receive. After reviewing data from people around this age over the following seven years, they concluded that the vaccine reduced the relative risk of dementia by 20%. According to the authors, their study, which is in prepublication form and has not been peer-reviewed, "leads to the conclusion that shingles vaccination is most likely an effective way to prevent or delay the onset of dementia".