DBS Testing in Infants May Miss Congenital Cytomegalovirus


Newborn dried blood spot testing is not sensitive enough to diagnose all cases of congenital cytomegalovirus (cCMV) in infants with sensorineural hearing loss.

Universal screening of newborns for congenital cytomegalovirus (cCMV) infection is the optimal method for identifying the infection as the cause of sensorineural hearing loss, according to a new study.

The study, presented at IDWeek 2019, examined the use of newborn dried blood spot (DBS) for detection of CMV in a retrospective review of electronic health records of infants who were referred to the Neonatal Infectious Disease Clinic at Nationwide Children’s Hospital for sensorineural hearing loss.

“The biggest takeaway from this research is that while attempts at retrospective diagnosis of congenital CMV infection by testing of the newborn dried blood spot may be successful in a minority of cases of infants with sensorineural hearing loss, it is not sensitive enough to diagnosis all cases,” Alexandra K. Medoro, MD, neonatal-perinatal medicine fellow at Nationwide Children's Hospital — The Ohio State University, told Contagion®. “Universal screening at birth would be the most comprehensive method to diagnosis congenital CMV infection.”

The study found that 17% of infants referred for evaluation of cCMV starting in 2015 had a positive CMV DBS. Meanwhile, DBS testing of 54 infants with known cCMV was positive in only 68% of cases.

“The number of patients who were referred to us who had not passed the newborn hearing screen but had not been tested for cCMV infection at that time was surprising,” Medoro told Contagion®. “There is still much work and education to be done to improve CMV testing of newborns who do not pass the newborn hearing screen.”

Early intervention can improve hearing outcomes for babies with sensorineural hearing loss due to congenital cytomegalovirus infection, which is likely an under-recognized cause of sensorineural hearing loss later in life. Clinicians should be aware of this possibility for babies who do not pass the newborn hearting screen, Medoro said.

To distinguish between prenatal, natal and postnatal CMV acquisition, babies should be test before 3 weeks of age.

“The neo-natal intensive care unit (NICUs) pertaining to Nationwide Children’s Hospital recently has started testing all babies for CMV on admission to the NICU utilizing a saliva specimen,” Medoro told Contagion®. “We already have seen the benefit of knowing whether the CMV infection was congenital or acquired in these high-risk infants. We are doing prospective surveillance to see how many more infants are identified, how many would have been missed, the interventions that were able to be made in a timely fashion, and assessing the neurodevelopmental outcomes of all infected infants.”

New research into the treatment and prevention of the illness also were discussed at IDWeek 2019, most notably investigators in Israel found that the antiviral drug valacyclovir reduced the rate of fetal CMV infection by 71%.

Another study found that administering CMV hyperimmune globulin (HIG) to women with primary CMV infection during pregnancy was not effective at decreasing risk of congenital CMV infection or fetal death in early pregnancy.

Last year, the US Food and Drug Administration approved Alethia CMV Assay Test System to assist in diagnosing cCMV with a saliva swab. Most people aren’t at risk of serious illness from the virus, but the infection can cause hearing problems, vision loss, microcephaly, developmental and motor delay, and seizures in people with compromised immune systems and newborns.

The abstract, Newborn Dried Blood Spot for Retrospective Diagnosis of Congenital Cytomegalovirus (CMV) Infection: It’s Time for Universal Screening!, was presented in a poster session on Saturday, October 5 at IDWeek 2019 in Washington DC.

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