A "harmless" virus carried by half of adults increases a person's risk of heart disease by a fifth, new research suggests.
Being infected with cytomegalovirus (CMV), which is a cousin of the herpes virus and spreads through contact or body fluids, makes a person 20 percent more likely to "get" heart disease.
CMV increases the amount of immune cells a person has in their blood. Such cells are associated with the buildup of plaque in the arteries, which can prevent blood from reaching the heart and trigger a deadly attack.
The study's author, Dr. Alejandra Pera, of Brighton and Sussex Medical School, said: "Our work shows that a CMV infection is responsible for the accumulation of a large number of immune cells that are related to coronary heart disease.
"They are a stronger indicator of the risk of cardiovascular death than age."
A "harmless" virus carried by half of adults can cause heart disease, research suggests (stock)
The researchers investigated how a CMV infection affects the health of a person's heart and the risk of premature death.
They analyzed 215 healthy people between 60 and 94 years old, as well as 27 from 19 to 32 years of age.
Blood samples were taken to determine how many immune cells memory participants had, as well as whether they carried CMV. Once infected, the virus remains in a person's body for the rest of his life.
Memory cells are a type of immune cell that responds quickly when it finds a pathogen a second time.
WHAT IS CYTOMEGALOVIRUS (CMV)?
Cytomegalovirus (CMV) is a common virus that is similar to herpes that causes cold sores and chickenpox.
Although previously thought to be harmless, research published in September 2018 suggests that it can trigger inflammation and the buildup of plaque in the arteries, both linked to heart disease.
CMV can also cause problems if a baby catches it during pregnancy.
Once a person becomes infected, CMV remains in their body for the rest of their lives.
The virus is transmitted by contact and body fluids.
Many do not know they have CMV; however, some may experience a high temperature, fatigue, nausea or sore throat when they become infected for the first time.
CMV is not treated unless it affects a baby or a person with a weak immune system, in which case antiviral medications are given. There is no vaccine
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Of the older participants, 122 carried CMV. They were included in the study because memory cells accumulate naturally with age, and CMV infection rates are higher among the elderly.
The results, published in the journal Theranostics, suggest that memory cells are twice as high in people infected with CMV. This may explain previous research linking CMV infections with stroke.
Although both CMV and memory cells are associated with older people, the link between the virus and cells persists even after age is counted.
Researchers believe that treating patients infected with CMV with antiviral therapies can reduce their risk of heart disease. There is no vaccine against CMV
Alternatively, targeting the IL-7 molecule, which triggers the production of immune cells after infection, can also make people infected with CMV less vulnerable to stroke.
Co-author Dr. Stefano Caserta, of the University of Hull, added: "We do not know if IL-7 may also be behind the accumulation of immune cells after CMV infection that some people may experience.
"However, it means that we are now discovering what we can do to fine-tune the immune responses, so that in the future we can adapt the therapies to individual cases."