Cold sores are a common problem that few people pay much attention to. Doctors tend to be unconcerned about them, too, and consider them to be little more than a nuisance. But one study shows a surprising link between one of the viruses that causes cold sores and the occurrence of immune cells that can damage the arteries around the heart.
While most people associate cold sores with the herpes simplex virus, the cytomegalovirus can also cause the unattractive sores and is in fact very similar to the herpes virus. The immune system normally controls cytomegalovirus and most people never even know they have it. (Many people probably assume it’s herpes.)
The study shows, however, that clinically-relevant numbers of a specific type of immune cells, known as CD28null CD4 T-cells, are only present when the cytomegalovirus is. Scientists have always known that these cells can damage cardiovascular tissue, but they believed they were a natural and unavoidable part of the aging process.
The researchers behind the study also found that people with certain tissue types (determined genetically) are more susceptible to having large numbers of CD28null and CD4 T-cells.
Lead author Dr. Alejandra Pera, from Brighton and Sussex Medical School (BSMS), said in a statement:
“While we had previously been aware of a link between these immune cells and cardiovascular damage, this study is the first to show that sufficient numbers to be damaging only occur in the presence of this infection.” 
A study published in 2017 shows that cytomegalovirus increases the risk of cardiovascular death by more than 20%, but the research didn’t identify the mechanism behind the increased risk.
Though the findings were startling and a bit frightening, it’s an important piece of information to be aware of, because it means that treating the infection could help reduce the damage from cardiovascular disease or prevent it from occurring.
Dr. Florian Kern, immunology leader at BSMS, explained:
“Our work suggests that cytomegalovirus infection is an important clinical factor to be considered in coronary heart disease and advanced atherosclerosis, and raises the possibility that treatment of the virus may be effective in the management or even prevention of coronary heart disease in a tangible proportion of patients. Tissue type might help identify those individuals most at risk.”
So if you wake up in the morning with a big, ugly cold sore on your lip, it might be worth it to get yourself checked out.
The study was published in the journal Theranostics.
 Science Daily