Herpes zoster vaccine has been shown to lower the risk of developing dementia

2025/04/07 Galarraga Aiestaran, Ana - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Osasuna
• Farmakologia
• Medikuntza
• Mikrobiologia

Older adults who received the herpes zoster vaccine have been shown to have a 20% lower risk of developing dementia in the next seven years by natural experimentation. The study, published openly in the journal Nature, confirms the previously suspected theory that viruses that affect the nervous system increase the risk of dementia. They also stress that the herpes zoster vaccine can have a much greater benefit than they thought in public health.

The herpes zoster virus has remained a varicella or astanafarreria virus. After having chickenpox, the virus does not go away; it stays in the nerve ganglia near the spinal cord for many years. In case of resurgence, it causes herpes zoster on the skin.

In this natural experiment (which was not previously designed for this purpose), the health records of Welsh seniors between the ages of 71 and 88 were analyzed and the data of those who received the herpes zoster vaccine were compared with those who did not. The criteria for the administration of the vaccine was age: those who were 80 years old on one day were not given (neither then nor thereafter), those who had not completed it were given (those who wanted to). So, even if they were the same age, a day apart, some had the vaccine and others didn’t. As a result, there was no common spill in similar studies: people who get vaccinated usually worry more about their health, so they tend to have a healthier lifestyle. This makes it difficult to know to what extent the vaccine prevents dementia, since a healthy lifestyle also plays a preventive role.

The comparison shows that the herpes zoster vaccine has a protective effect. Specifically, there were 20% fewer cases of dementia among the vaccinees. In addition, the effect was even more pronounced in women. And there were no differences in other diseases or health parameters; only in dementia. Therefore, the researchers confirm that the decrease in cases of dementia is due to the vaccine.