Hearing Loss in Infants and Children with Asymptomatic Congenital Cytomegalovirus Infection: An Update in Diagnosis, Screening and Treatment.

Cytomegalovirus (CMV) represents the most prevalent cause of congenital viral infection in newborns and the leading non-genetic etiology of sensorineural hearing loss (SNHL) in children. Notably, only 10-15% of congenitally infected infants possibly present with classic clinical symptoms at birth, including Small for gestational age, Microcephaly, Petechiae or purpura, Blueberry muffin rash, Jaundice, Hepatomegaly, Splenomegaly and abnormal neurologic signs. In contrast, approximately 90% of infected neonates exhibit no apparent symptoms initially. Current research predominantly focuses on symptomatic cases due to their severe acute presentations and high rates of long-term sequelae (40-60%), including SNHL and neurodevelopmental impairments. However, significant controversy persists regarding the management of asymptomatic infants. Emerging evidence reveals that 8-15% of asymptomatic carriers develop Late-onset Hearing Loss (LOHL) beyond the neonatal period. Additionally, 5-10% may manifest neurodevelopmental abnormalities including mild intellectual disability, learning difficulties, or motor coordination disorders. Crucially, given the substantial population of asymptomatic cCMV cases, these delayed complications account for 30-40% of all cCMV-related long-term morbidity, underscoring their considerable public health impact. This review synthesizes current evidence and controversies regarding cCMV-related SNHL in asymptomatic or mildly symptomatic children, with a focus on screening, diagnostic classification, and antiviral management gaps, to heighten clinical awareness of this underrecognized cause of hearing loss.