Integration of Congenital Cytomegalovirus testing via Dried Blood Spot into neonatal hearing screening program: a valuable further approach?

Background. Congenital Cytomegalovirus (cCMV) is the most common cause of non-genetic hearing loss in childhood. Currently, universal CMV screening is not routinely conducted in Italy. This study aimed at investigating the contribution of cCMV in children with hearing loss identified via integrated neonatal hearing screening (NHS) program conducted in Lombardy (Northern Italy) from 2014 to 2017. Materials and Methods. Infants who failed NHS assessed via otoacustic emissions (OAE) and auditory brainstem response testing (ABR) in Lombardy (birth cohort of 2014-2017) and investigated for CMV-DNA by using nucleic acid extraction and PCR in-house protocol on stored newborns screening card (Dried Blood Spot-test; DBS-test) were included in this study. Deafness was defined by a threshold of hearing ≥20 dB by ABR; all investigated DBS were collected within 3 days of life. Results. Overall, 71 children (median age: 3.4 months; lower-upper quartile: 2-5.3 months; male: 57.7%) were included. Most of them (51/71; 71.8%) presented bilateral hearing loss that showed a symmetrical pattern in 78.4% (40/51) of case. ABR resulted ≥70 dB (severe/profound deafness) in half of children (36/71; 50.7%). 7% (5/71) of children tested positive for cCMV. The percentage of severe/profound deafness was statistically higher in children with cCMV infection than in the others (100% vs 47%, p= 0.028). Conclusions. Using DBS-test based on NHS program allowed to identify cCMV infection in 7% of children failed NHS in their first months of life. Move forward on a target-CMV screening strategy could help clinicians in differential diagnosis and baby management. Further investigation on broader birth cohort will be planned.