Herpes may double the risk of dementia, research suggests

A recent study by Swedish researchers suggests that people diagnosed with herpes may have twice the risk of developing dementia compared to those who have not been infected with the virus. However, although the discovery reinforces previous studies that show a relationship between both health conditions, it is still not known why this happens.

Herpes is a viral infection that causes blisters in the mouth (cold sores) or in the genital area (genital herpes). This is a very common disease – according to the WHO (World Health Organization), 70% of the world's population has already come into contact with the herpes virus. Transmission can occur through contact with the saliva or mucous membrane of a person infected with the virus.

Once infected, the pathogen can remain in a person's body for the rest of their life, in an inactive form. The reactivation of the virus and the emergence of symptoms can happen due to factors such as emotional stress, sun exposure, fever or a drop in the immune system.

About the study

A search was published at the beginning of February in Journal of Alzheimer's Disease and followed a thousand people aged 70 and over for 15 years. At the start of the study, no participants had dementia. During this period, serum samples were analyzed to detect antibodies against the herpes simplex virus, and diagnoses and medication prescriptions were collected from participants' medical records.

According to the researchers, 82% of the participants contained the herpes virus in their bodies. The incidences of dementia and Alzheimer's during the study, from all causes, were 7% and 4%, respectively. According to research results, carrying the herpes virus was associated with a doubled risk of developing dementia.

“What's special about this particular study is that the participants are approximately the same age, which makes the results even more reliable, as age differences, which are otherwise linked to the development of dementia, cannot be confuse the results”, explains Erika Vestin, medical student at Uppsala University and main author of the study.

“It is exciting that the results confirm previous studies. More and more research evidence is emerging that, like our findings, points to the herpes simplex virus as a risk factor for dementia,” continues Vestin.

Despite the discovery, more studies are needed to understand what the causality is: whether it is the virus that causes dementia or whether there is an indirect link. Furthermore, in-depth investigations are needed to understand whether medications for treating herpes can reduce the risk of dementia.

“The results could boost research into dementia in order to treat the disease at an early stage, using common medicines against the herpes virus, or prevent the disease before it occurs”, adds Vestin.