CMV (cytomegalovirus) is a little-known virus. However, it is widespread globally, and more than half of the U.S. population is at risk of being infected by this virus by the age of 40.
According to Science Alert, CMV belongs to the same virus family as the viruses that cause cold sores and chickenpox, which means they reside in people’s bodies for life. Most children and adults experience a mild initial infection, sometimes without any symptoms. Moreover, a healthy immune system can usually keep CMV in check, so people are often unaware that the virus is living in their bodies.
Ms. Laura Gibson, an expert in infectious diseases and immunology, has focused her research on why understanding CMV is important for everyone. One key reason is that CMV can be transmitted from mother to fetus during pregnancy.
Congenital CMV (cCMV) is the most common infection before birth. It is the leading infectious cause of congenital disabilities. Each year, many children are affected by cCMV, with some familiar conditions such as Down syndrome and fetal alcohol syndrome (FAS).
Compared to later stages of pregnancy, CMV infection during the first trimester poses the highest risk for stillbirth or severe effects, as the immune system and organs like the brain are developing.
CMV is Rarely Diagnosed Early in Pregnancy
Routine screening for rubella, HIV, and syphilis is common in early prenatal care in the U.S. However, if CMV can infect the fetus and cause congenital disabilities, why aren’t pregnant individuals tested and treated for this virus?
The reason is that prenatal CMV screening is not a standard of care due to some limitations of current testing methods. Testing can provide information about whether parents are infected with CMV, but it cannot fully predict the risk of transmission to the fetus or severe symptoms.
Moreover, prenatal screening for a healthy person with a normal pregnancy often does not provide much useful information. This is because anyone can give birth to a baby infected with cCMV, regardless of whether they tested positive or negative for it earlier in pregnancy. CMV testing can be helpful for pregnant individuals experiencing acute illness, such as fever and prolonged fatigue, or those with abnormal fetal ultrasound results.
Even with more accurate tests, there are currently no medical interventions approved by the U.S. Food and Drug Administration (FDA) to reduce the risk of CMV infection in the fetus.
Antibodies against CMV appear to reduce the likelihood of transmission to the fetus when introduced at conception or during the first three months, but CMV is rarely diagnosed early in pregnancy.
Pregnant women should undergo early CMV screening. (Photo: FirstCry Parenting).
CMV Screening for Newborns
Currently, some fertility centers offer early CMV testing. However, most states in the U.S. do not require CMV testing for newborns. Ms. Gibson’s team surveyed 33 hospitals in Massachusetts from late 2020 to early 2021 and found that fewer than half of pregnant individuals routinely screened newborns for cCMV infection.
Therefore, standardizing public health education and CMV screening guidelines could help reduce the incidence and impact of cCMV disease on children.
So far, 17 states in the U.S. have enacted laws requiring cCMV education or targeted screening for newborns meeting certain criteria. On the other hand, designing, funding, and implementing a new newborn screening program is very complex and time-consuming.
Most newborns infected with cCMV are physically stable at birth and develop normally throughout their lives. This raises questions about the benefits of CMV screening for those children.
However, newborns can still have undetectable abnormalities at birth, and there is no way to predict whether they will face health issues later on.
Thus, without screening all newborns for CMV, those who appear normal at birth will not be thoroughly evaluated, considered for treatment, or monitored for later developmental impacts, such as hearing loss.
Advocating for CMV Awareness
Reducing the incidence of cCMV is unlikely to be effective without raising awareness. Most people have never heard of CMV or do not know what to do to lower the risk of CMV infection during pregnancy.
Infections like CMV can easily spread among children in daycare settings through group play, meals, and diaper changes. Even when CMV is present in saliva and urine weeks or months after infection, children may still appear very healthy.
Therefore, when a caregiver of a pregnant individual comes into contact with these bodily fluids, they too may become infected.
For those who are pregnant, simple behaviors such as kissing a child on the head instead of on the lips, not sharing food or utensils, and washing hands frequently can significantly reduce the risk of CMV infection.
