Researchers at Uppsala University in Sweden found that people infected with the herpes simplex virus, which commonly causes cold sores, had roughly double the risk of developing dementia. The findings appeared in a study summarized by the Journal of Alzheimer’s Disease. These results add to a growing body of work exploring how herpes simplex virus infection may influence brain health and cognitive aging.
In the United States, estimates suggest that a large portion of adults have been infected with herpes simplex virus at some point in their lives. Symptoms such as inflamed, blistered lips tend to emerge when the immune system is stressed, or when the body faces intense sun exposure, cold winds, or significant adversity. These flare-ups are a sign that the virus is present, often remaining dormant in nerve cells and potentially reactivating under trigger conditions.
The Swedish study analyzed health data from more than a thousand participants and found that herpesvirus infection was associated with an increased risk of both Alzheimer’s disease and dementia over time. The research unfolded in two phases: first gathering comprehensive health information from volunteers and then monitoring them over an extended period to observe long-term outcomes. At the end of the follow-up, 71 participants developed some form of dementia and 36 were diagnosed with Alzheimer’s disease. Among the individuals who developed these conditions, a large majority were found to have been infected with the herpes simplex virus at some point. Statistical analysis indicated that carrying the virus roughly doubles the likelihood of developing dementia compared with those without the infection.
Several theories circulate in the scientific community about how the herpes virus might influence brain health. One idea is that the virus could contribute to the buildup of toxic protein aggregates in the brain, a hallmark often linked with dementia. The precise biological mechanisms behind this potential connection are still under investigation, with researchers pursuing clearer answers about how viral activity might interact with brain cells over time.
Experts emphasize that while the association is noteworthy, it does not prove that herpes simplex virus infection causes dementia. The pathway could involve multiple interacting factors, including genetics, overall health, and other environmental influences. Ongoing work aims to clarify whether antiviral strategies or other interventions could modify risk in people known to carry the infection, and what that could mean for prevention efforts in aging populations.
Previous investigations have proposed various risk markers that might signal an elevated likelihood of developing Alzheimer’s disease. The new findings contribute to a broader effort to understand how common infections may intersect with neurodegenerative processes, guiding future research directions and, potentially, public health recommendations. In the meantime, maintaining general brain health through safe practices, balanced lifestyle choices, and regular medical care remains a prudent approach for everyone, especially as aging populations grow and the burden of dementia continues to rise.