Dr. Pablo Sanchez, a pediatrician at the University of Texas Southwestern Medical Center in Dallas, says the findings are important because few newborns display any clinical signs of cytomegalovirus infection.
Sanchez is co-author of a national study that found saliva enabled doctors to correctly identify every baby born with the infection when the saliva sample was liquid and 97.4 percent when dried saliva specimens were used.
"Babies who test positive can be monitored for possible hearing loss, and if needed, provided with appropriate intervention as soon as possible," Sanchez says in a statement.
Cytomegalovirus is the most common infection passed from a mother to a child. Each year, as many as 10 percent to 50 percent of the 20,000 to 30,000 babies infected with cytomegalovirus at birth are at risk for having or developing hearing loss.
The study, published in a recent issue of The New England Journal of Medicine, involved nearly 35,000 infants from well-baby nurseries at seven U.S. hospitals from June 2008 to November 2009.
Most swabs were taken when the infants were one day old. Those who tested positive for cytomegalovirus infection were enrolled in a follow-up program to monitor their hearing every six months until age 4.
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