Cytomegalovirus (CMV) is a widespread herpes virus that infects people of all ages and remains in the body for life once contracted. Even as it often causes no symptoms in healthy individuals, it can pose serious risks for certain groups, particularly newborns and people with weakened immune systems.
According to the CDC, nearly one in three children in the United States is infected with CMV by age 5, and over half of adults have been exposed by age 40. Most people with CMV show no signs of illness and may not even understand they carry the virus. When symptoms do occur in healthy individuals, they are typically mild and can include fever, sore throat, fatigue, and swollen glands—sometimes resembling mononucleosis or causing temporary liver issues.
However, the virus becomes a significant concern in specific populations. In people with compromised immunity—such as those undergoing chemotherapy, organ transplant recipients, or individuals living with HIV—CMV can reactivate and lead to severe complications affecting the eyes, lungs, liver, esophagus, stomach, and intestines.
Perhaps most critically, CMV is the leading infectious cause of birth defects in the United States. When a pregnant person passes the virus to their developing baby, it results in congenital CMV infection. About one in 200 babies is born with this condition, and roughly one in five of those infants will experience birth defects or long-term health problems.
The most common lasting issue linked to congenital CMV is hearing loss, which affects approximately 25% of affected children and may be detected at birth or emerge later in childhood. Other potential complications include developmental delays, vision problems, seizures, and issues with the liver, spleen, lungs, or growth.
Because the virus spreads through bodily fluids—including saliva, urine, blood, semen, and breast milk—prevention focuses on hygiene practices, especially for those who are pregnant or work closely with young children. Regular handwashing, avoiding sharing food or utensils, and minimizing contact with saliva when caring for infants can reduce transmission risk.
Although there is currently no approved vaccine to prevent CMV infection, ongoing research aims to develop effective immunization strategies. For now, awareness and preventive measures remain key to protecting vulnerable populations from the potential harms of this common but often overlooked virus.
