Birth prevalence, clinical sequelae, and management of congenital cytomegalovirus infections in Australia, 1999-2023: a national prospective study.

Objectives: To investigate the birth prevalence, clinical manifestations, and management of congenital cytomegalovirus (CMV) infections in Australia, 1999-2023.

Study design: Longitudinal observational study; analysis of prospectively collected Australian Paediatric Surveillance Unit (APSU) data.

Setting, participants: Australia, 1 January 1999 - 1 January 2024.

Major outcome measures: Number of definite congenital CMV infections during study period and after the establishment of universal neonatal hearing screening (1 January 2004); clinical sequelae of definite infections; proportion of infants with symptomatic definite infections treated with antiviral medications.

Results: During 1 January 1999 - 1 January 2024, 586 cases of congenital CMV infection were reported to the APSU (8.15 [95% confidence interval, 7.50-8.83] infections per 100 000 births), including 479 definite infections (82%). The most frequent sequelae of definite infections were small for gestational age or intrauterine growth restriction (135 infants, 28.2%); neurological conditions (most frequently: deafness [183, 38.2%], microcephaly [89, 18.6%]); liver disease with jaundice (130, 27.1%), hepatomegaly (75, 15.7%), or hepatitis (85, 14.7%); and bone marrow conditions (most frequently: thrombocytopaenia [139, 29.0%], petechiae/purpura [89, 18.6%]). Of 168 Guthrie card tests (newborn blood spot screening), 154 (91.7%) were CMV-positive (polymerase chain reaction DNA detection), including 143 that provided the sole reason for classifying the cases as definite congenital CMV infections. During 1 January 2004 - 1 January 2024, 447 of 506 cases (88.3%) were definite congenital CMV infections, of which 366 (81.9%) were symptomatic; 116 of these infants (32%) were treated with antiviral medications.

Conclusions: The number of reported definite congenital CMV infections during 1 January 1999 - 1 January 2024 was only 1.0% of the number expected in Australia on the basis of their estimated prevalence in developed countries. The number of reported cases has continuously increased since 1999, as has the use of antiviral therapy. Surveillance of congenital CMV infections, the major infectious cause of congenital malformations, needs to be expanded to fully assess their prevalence and the associated disease burden, and to inform prevention strategies.