Congenital cytomegalovirus infection--a question of screening.

• Vol 9 • May 2007 392 Routine serologic screening of pregnant women or newborns has never been recommended by any public health authority in any country. As a result of demands by pregnant women and the fear of litigation, most obstetricians in Israel do test pregnant women for cytomegalovirus, and they are confused by the findings. CMV infection is the most frequent congenital infection, affecting between 0.2% and 2.5% of all live births, and the most common cause of deafness and impairment of intellectual function among infants [1-7]. Each year in the United States, hundreds of children die and thousands develop disabilities such as mental retardation, hearing loss and vision loss due to congenital CMV infection [1-4]. More children are affected by congenital CMV (8000 children per year) than by other childhood disability conditions, such as Down syndrome (4000 children/year), fetal alcohol syndrome (5000 children/year), and spina bifida and congenital rubella syndrome – which have been eliminated and for which screening during pregnancies is still routinely performed [5]. The prevalence of congenital CMV infection in Israel was found to be around 0.7% [6]. Since 15–20% of the annual 145,000 pregnancies in Israel are born to seronegative mothers [7], 21,750–29,000 women are at risk of developing primary CMV infection during pregnancy. With a 1–8% risk of primary infection among seronegative pregnant women and a 40% transmission rate [1-4], 348 to 464 cases of congenital CMV infection resulting from primary infection are expected each year. Since 30% of the infected newborns become symptomatic [1-4], 105 to 139 symptomatic infections are expected each year. Furthermore, 116,000–123,250 women are at risk each year for developing non-primary CMV infection during pregnancy, with a transmission rate of 1% [8]. The percentages of seropositive pregnant women undergoing reactivation during pregnancy and the percentages of symptomatic newborns among those infected are unknown. Boppana et al. [9] and Ahlfors et al. [10] found that among symptomatically infected newborns for whom the immune status of the mothers was defined, almost 50% were born to mothers with non-primary CMV infection. Thus, an additional unknown number of congenital CMV infections resulting from non-primary infection should be added. In the 1990s, the overall disease burden associated with congenital CMV infection was estimated to cost the U.S.