Not Just Cold Sores: Herpes Simplex Virus Can Cause Dementia

If you have herpes, you may think cold sores and mild sexual health embarrassment are the worst of your wellness worries, but according to researchers from the Columbia University Medical Centre, your cognitive wellbeing may also be at stake. Led by Dr Mira Katan, the scientists discovered that, with time, the herpes simplex virus may also lead to cognitive problems, memory loss, and dementia.

1,625 adults around the age of 70, who were all residents of northern Manhattan, participated in the study, which was published in the journal Neurology. The researchers screened for dementia by measuring the volunteers’ attention, memory, and language skills with a cognitive assessment called the Mini-Mental State Examination (MMSE). The researchers also tested the participants’ blood samples for several common infections, including herpes simplex type 1 virus (HSV-1), which causes cold sores; herpes simplex type 2 (HSV-2), which causes genital herpes; cytomegalovirus; Chlamydia pneumoniae, a common respiratory infection; and Heliobacter pylori, a type of stomach bacteria.

The amount of exposure to the viral and bacterial pathogens was called “infectious burden”, and participants on the higher end of this scale were found to be 25% more likely to score below average on cognitive tests. The results still held even when researchers accounted for other factors that could have affected their cognitive function, like age, education, and drug and alcohol use. However, the researchers did not believe that the damage caused by infections progresses over a prolonged period, as they found no association between infectious burden and decline in cognitive scores over time.

Dr Katan stressed that the current study only shows an association between cognitive impairment and infectious burden, albeit a strong one. She said that more research is needed to replicate these results. Her previous research has shown that infections can amplify your body’s inflammatory response over time, which has been tied to cognitive impairment and stroke.

You can reduce this inflammation if you exercise, which may explain why sedentary people showed greater cognitive impairment than those who exercised regularly. Though he was not involved in the study, Dr Nunzio Pomara of the Nathan S. Kline Institute for Psychiatric Research in Orangeburg, New York, said he was ‘quite happy to see that, at least in some instances, there could be a potentially treatable [cause of] cognitive dysfunction.’