Two studies claim that an infection of herpes simplex virus can increase the risk for Alzheimer’s disease. Researcher Hugo Lövheim, associate professor at the Department of Community Medicine and Rehabilitation, Geriatric Medicine, Umeå University, said, “Our results clearly show that there is a link between infections of herpes simplex virus and the risk of developing Alzheimer’s disease. This also means that we have new opportunities to develop treatment forms to stop the disease.”
In two large epidemiological studies, Hugo Lövheim and Fredrik Elgh, professor at the Department of Virology, have finally confirmed the link between cold sores and dementia. In one study 3,432 participants were followed for 11.3 years on average, and the researchers found a reactivated herpes infection doubled the risk of developing Alzheimer’s disease in these patients. The second study looked at 360 people with Alzheimer’s disease and an even number of control groups. Researchers took samples from patients at an average of 9.6 years before diagnosis, and found a doubled risk of developing Alzheimer’s disease in patients who carried the herpes simplex virus.
Researchers have always thought there was a connection between a common herpes virus, herpes simplex virus type 1, and Alzheimer’s disease. The virus is carried by nearly everyone and once infected, a person carries the virus for the rest of their life. The hypothesis is that the weakened immune system in the elderly allows the virus to spread further to the brain, which could start the process of Alzheimer’s disease.
“Something which makes this hypothesis very interesting is that now herpes infection can in principle be treated with antiviral agents. Therefore within a few years we hope to be able to start studies in which we will also try treating patients to prevent the development of Alzheimer’s disease,” says Hugo Lövheim.