Cytomegalovirus (“CMV”) is a common virus that infects one in every two people in many developed countries. Most CMV infections are “silent,” meaning most people who are infected with CMV exhibit no signs or symptoms. However, CMV can cause serious disease in newborns when a mother is infected during pregnancy – this is known as congenital CMV infection.
Hearing loss is a common manifestation of congenital CMV infection; in fact, CMV is the most common non-genetic cause of hearing loss. Some evidence suggests that antiviral treatments for CMV may improve audiologic outcomes; a 2015 study published in the New England Journal of Medicine found that six months of treatment with valganciclovir reduced rates of hearing loss. However, congenital CMV infection often goes undetected because the majority of affected infants do not present symptoms at birth. Some research has shown that routine screening of newborns could allow CMV-infected infants to receive better care.
Utah CMV Legislation
Given the high incidence of hearing loss in infants with congenital CMV infection, the possibility for hearing loss in otherwise asymptomatic newborns, and the potential for improved outcomes with treatment, Utah led the United States in passing legislation designed to improve CMV awareness and screening for those most at risk.Utah Department of Health CMV Public Health Initiative WebpageDespite the seriousness of congenital CMV infection, only 7% of men and 13% of women are aware of the condition, according to a 2012 study published in Preventive Medicine. Utah’s public health program addresses this problem by raising awareness of CMV including routes of transmission, associated birth defects, and prevention strategies.
Additionally, Utah requires that any infant who fails two newborn hearing screenings within two weeks of birth undergo testing for CMV within three weeks of birth (three weeks is the cutoff after which congenital CMV cannot be differentiated from CMV acquired after birth). Infants who test positive for CMV have the option of treatment with antiviral therapies, which may decrease the risk of permanent hearing loss.
Outcomes of Utah CMV Legislation
In February, a team of researchers at the University of Utah and the Utah Department of Health published a study evaluating the effectiveness of the Utah screening program in the journal Pediatrics.
The researchers analyzed all birth records in the two years after the CMV legislation took effect. The researchers identified all infants who failed hearing screens after birth to determine how many completed CMV screening and subsequent diagnostic hearing evaluations. They also examined factors such as the ages and education levels of the mothers, whether the births took place at hospitals, and other variables to identify groups that were more or less likely to complete CMV screening and diagnostic hearing evaluations.
Out of 103,868 infants born in Utah in the two years after the new law took effect, 509 failed two hearing screenings. 314 (61.7%) of the 509 newborns who failed multiple hearing screens were tested for CMV, with 234 tested within three weeks of birth. 14 (6%) of these 234 newborns tested positive for CMV – thus, nearly 3% of the 509 otherwise asymptomatic newborns were ultimately diagnosed with congenital CMV infection.
These infants would likely have not been diagnosed with CMV were it not for the introduction of the screening program. Additionally, the study revealed that infants whose mothers did not have at least a bachelor’s degree and those born outside of a hospital were less likely to be screened for CMV after failing multiple hearing tests.
Utah’s new legislation has successfully identified cases of CMV that would otherwise have remained undetected. These results are encouraging, as it allowed more than a dozen newborns with asymptomatic congenital CMV infection to receive timely treatment that increased their chances of retaining normal hearing.
While the new screening program is effective, one in four of these children will likely suffer from permanent hearing loss. Additionally, universal screening of newborns for CMV has significant costs which may limit broader adoption in other U.S. states and internationally.
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CMV Vaccine Candidate
Approximately one out of every 150 babies is born infected with CMV. Of the nearly four million infants born in the United States each year, more than 25,000 have evidence of CMV infection at birth. Approximately 80% of these CMV-infected newborns grow up completely healthy. However, the remaining 20% develop lifelong disabilities, some of them severe, including deafness, blindness, and mental retardation.
VBI is developing a vaccine to prevent CMV infection. We believe that developing a vaccine to prevent CMV offers the best chance of substantially eliminating congenital CMV infection and the resulting birth defects. Learn more >>