Secondary Maternal Cytomegalovirus Infection—A Significant Cause of Congenital Disease

To the Editor. In November 1999 a comprehensive report by us on a Swedish long-term prospective study of congenital cytomegalovirus (CMV) infection was published in the Scandinavian Journal of Infectious Diseases. 1 The main observation—already reported in 19842—was that secondary (recurrent) maternal CMV infection seems to be an important cause of congenital CMV disease. Data from England (1983)3 and Belgium (1999)4indicate a similar situation as in Sweden. While our report (1999) was in press, a US report from Alabama (1999)5 was published in the present journal with the same signification. The new US data were contrary to those reported by the same group as late as in 1992.6,7 The new unanimous findings have weighty consequences. The Swedish study1 was based on observations made in infants born in 1977–1985. Congenital infection was identified from newborn virologic screening at the General Hospital in Malmo, Sweden. Maternal infections—primary or secondary (reactivated latent or reinfection with a new strain)—were categorized with conventional serological tests and criteria. Sera were regularly sampled from the mothers during pregnancy and at delivery; often preconceptional sera were also available. A few years after starting, we detected the first case of secondary maternal infection causing infant neurologic disease.8 Some years later it was evident that this case was not a unique one; 4 of the 5 infants shown to have symptoms from the central nervous system (CNS) were born to mothers with confirmed or presumed secondary infections.2 In our recent report we presented the whole material of 16 474 virologically screened newborns, 76 (0.5%) of them with confirmed congenital CMV infection. Among 60 followed up for at least 7 years, 11 had symptoms from CNS. Investigation of the mothers showed that symptomatic congenital infection occurred in 5/27 (19%) primary, 6/23 (26%) …