In the April Clinical Laboratory News, writer Deborah Levenson describes the arguments for and against universal screening for congenital cytomegalovirus (CMV) in newborns, a disease that can lead to hearing, language, speech, and vision problems, and other disabilities.

“Despite studies deeming it cost-effective and research linking antiviral treatment to better outcomes, some hearing loss experts say that current targeted screening programs miss many asymptomatic infants, while no studies show antiviral drugs improve longer-term hearing outcomes in either symptomatic or nonsymptomatic babies,” Levenson wrote.

Yet, the potential to find infants at earlier stages of infection before acute hearing loss manifests has others advocating for the addition of CMV screening to state newborn screening panels.

The Centers for Disease Control and Prevention’s (CDC) decision to recommend polymerase chain reaction (PCR) testing of saliva as the standard diagnostic test for the virus, has been a game changer in this debate—as it finally introduces a rapid, accessible screening tool for detecting CMV.

Recent studies have also yielded some encouraging results on the effectiveness of CMV screening. Utah was the first state in the U.S. to mandate a CMV test several weeks after an infant fails hearing screening at birth (excepting cases where a parent declines). The University of Utah, which published a study in Pediatrics on the effects of this program, determined that the percentage of infants who failed newborn hearing screenings and subsequently underwent diagnostic CMV evaluations went up by 21% after the screening program took effect.

“The authors concluded that incorporating CMV screening into an established newborn hearing screening program is a ‘viable option’ in identifying CMV-infected babies,” Levenson wrote.

Another study conducted by the CMV and Hearing Multicenter Screening (CHIMES) study examined the effectiveness of using targeted CMV screening to identify infected babies. Out of a pool of nearly 100,000 infants, researchers using this targeted approach were able to identify nearly 60% of those who had CMV-related hearing loss, although it did miss a fair number of neonates with hearing loss as well as infants at risk for late-onset hearing loss.

The CHIMES investigators in another study did discover a cost benefit to conducting both universal and targeted screening. The antiviral drug valganciclovir hydrochloride, which has been shown to improve hearing and neurocognitive outcomes in young children who started treatment right after birth, has cast additional attention on CMV newborn screening, Sallie Permar, MD, associate professor of pediatrics at Duke University School of Medicine in Durham, North Carolina, told CLN.         

Experts caution that a number of hurdles exist to establishing a universal newborn screening protocol for CMV. “Because most state newborn screening tests look for genetic conditions and are performed on dried blood spots, states would need new infrastructures to collect and test saliva or urine. These specimens currently make better samples than blood because more virus is shed in them,” said Albert Park, MD, chief of pediatric otolaryngology and professor of surgery and of pediatrics at University of Utah, and a senior author of Utah’s CMV screening legislation. 

Pick up the April CLN to learn more about upcoming research to better inform the necessity for universal CMV screening, and what needs to be resolved before issuing a federal screening protocol.