5 Things To Know About A Common Virus You’ve Probably Never Heard Of

Cytomegalovirus, or CMV, is a virus that often shows no symptoms in adults but can cause serious health issues in newborn babies.

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We’re kicking off an ongoing interview series dedicated to women’s health issues called Answer This. Today’s edition: CMV. Cytomegalovirus is a virus typically found in a majority of adults, yet many people have likely never even heard of the condition. Because the virus can have harmful effects on newborns, it’s important to be aware of the risks and implications of CMV for early detection and treatment.

Here are the most important facts you should know about CMV, from our interview with Dr. Gail Demmler-Harrison, an infectious disease expert at Texas Children’s Hospital. See the full episode of Answer This with NowThis correspondent Zinhle Essamuah and Dr. Demmler-Harrison here.

1. CMV can cause serious, long-term effects in newborns

About one in every 200 babies can have what is known as congenital CMV, which means the virus is transmitted from mother to baby. According to Demmler-Harrison, roughly 90% of babies born with the virus will show virtually no symptoms at all. But 20% of them can go on to have progressive hearing loss. Researchers are still working to figure out why some newborns experience hearing loss, and others don’t.

“Sometimes, unfortunately, the virus can affect the baby's brain. They can be born with what's called microcephaly or small head, or their brain can be malformed or can have calcifications or cystic malformations,” Dr. Gail Demmler-Harrison, infectious disease expert at Texas Children’s Hospital told NowThis. “It can cause vision loss and blindness.”

2. Many adults become infected and don’t know

“It's probably the most common virus most people have never heard of,” Demmler-Harrison said. “It's a common DNA virus, most of us will be infected with it sometime in our life.”

According to the Centers for Disease Control and Prevention, more than half of adults will contract CMV before the age of 40, but most healthy immune systems will prevent a person from having any symptoms. Adults who do experience symptoms may have a fever, sore throat, fatigue, or swollen glands. In more serious cases, CMV can cause issues with the eyes, lungs, liver, esophagus, stomach, and intestines.

3. CMV is not an airborne virus

Unlike some other viruses, a person cannot become infected with CMV just by being around another person who has it. CMV can only be transmitted through bodily fluids including saliva, urine, blood, tears, semen, and breast milk, according to the CDC. Demmler-Harrison said toddlers “are virtual hot zones for CMV.”

“They pass it very frequently between themselves in daycare centers, in group settings, and home care settings,” Demmler-Harrison continued. She also said that expecting mothers should take precautions to prevent contracting the virus from their young children while they’re pregnant, including washing their hands after changing diapers, avoiding eating or drinking something after your child has, and avoiding kissing them on or around the lips and face.

4. How do you know if a newborn has CMV?

A newborn baby can be tested for CMV through a saliva, urine, or blood sample, according to the CDC. Some newborns will present various symptoms of the virus including a small rash, an enlarged liver or spleen, abnormalities of their liver enzymes, or low platelets in their blood. Demmler-Harrison said that oftentimes, the hearing loss can happen from one month to many years after the child is born, and can be in one ear or both.

“In the newborn, sometimes the hearing loss is present at birth and can be picked up through routine newborn hearing screening,” Demmler-Harrison said.

5. How to treat CMV

Both the CDC and Demmler-Harrison said that detecting CMV as early as possible is the first step to preventing severe symptoms including hearing loss. Most healthy adults and children who have CMV likely won’t show symptoms and therefore don't need treatment. If someone with CMV does become ill from the virus, a doctor can treat the symptoms depending on severity, according to the Mayo Clinic. Researchers are also developing new treatments to help combat the long-term effects of CMV.

See our first installment of Answer This here, where we explore CMV, common virus you've probably never heard of that can affect people of all ages, but can have long-term negative health effects for some newborn infants. We spoke to Dr. Gail Demmler-Harrison, an infectious disease doctor and professor at Texas Children's Hospital. Additional resources on CMV can be found here and here.