CMV at birth linked with delayed sensorineural hearing loss

The most powerful risk factor for delayed hearing loss is cytomegalovirus (CMV)-related symptoms at birth, and longer duration of CMV shedding may also predict delayed hearing loss, according to a recently published study.

Researchers from the University of Alabama and CDC researchers retrospectively identified 580 children born between January 1980 and October 1997 and who had been diagnosed with CMV by virologic testing of urine. The infants must have had at least one hearing evaluation from one follow up visit.

The researchers said that the occurrence of positive CMV cultures typically dropped to 50% by the time a child reached age 3, and to approximately 5% at 7 years.

Thirty-eight children developed a delayed loss of hearing, which researchers said was strongly connected with symptomatic infection at birth. Some patients reported a delayed loss of hearing with an older age at the last culture-positive visit.

UAB and CDC researchers also noted, however, that many asymptomatic children also developed delayed hearing loss. “Observed rates of delayed hearing loss were 0.79 per 100 person years for children asymptomatic at birth and 4.29 per 100 person-years for children symptomatic at birth,” the researchers concluded.

Based on those calculations, the researchers predicted between ages 6 months and 8 years, delayed hearing loss expectancy would be about 6.9% in asymptomatic children, and 33.7% in symptomatic children. –Erin Hopkins

PIDJ. 2009;28 (6): 515-520

This is a well-structured study from the leading group of congenital CMV researchers. It again illustrates why CMV is such an important pathogen in pediatrics. Pediatricians should be diligent in considering CMV in babies with symptomatic disease, and public health officials should continue to analyze methods which could be adapted for widespread, if not universal, CMV screening in newborns.

David Kimberlin, MD

IDC Editorial Board