Grant: Project Grant

It is estimated that 1 in 200 babies in North America are born with congenital cytomegalovirus infection (cCMV). Of those, ~20% will develop permanent neurologic problems - primarily hearing loss and developmental disability. Most newborns with cCMV (~90%) have either no or very mild symptoms, which is why very few cases of cCMV are diagnosed. Missed cases are important because even those with no symptoms at birth have a high risk of future problems such as hearing loss. There is evidence that these children's development can be optimized through early interventions (antivirals; hearing monitoring and use of hearing aids; speech therapy). For these reasons, population-based cCMV screening is predicted to be both beneficial and cost-effective. However, knowledge gaps regarding cCMV remain. For example, it is unclear which asymptomatic children will go on to have negative health outcomes. Newborn Screening Ontario introduced an Expanded Hearing Screen in August 2019 to identify children at risk of hearing loss by testing all babies for cCMV as well as genes that cause hearing loss. This is the first population-based newborn cCMV screening program in the world, using dried blood spots (DBS) collected at birth for disease screening. While sensitivity of prospective CMV testing using DBS is estimated at ~62%, sensitivity of CMV testing from saliva approaches 100%; however it requires collecting saliva in addition to DBS from newborns. Knowing both the clinical sensitivity (ability to detect cCMV cases who will develop sequelae) and analytic sensitivity (ability to detect all cCMV cases) will be important to the success of the NSO program. We will follow cCMV cases identified in a prospective cohort to determine the rates of hearing loss and neurodevelopmental problems. Study objectives include: 1. Determining the clinical and analytic sensitivity of CMV PCR testing on DBS versus saliva samples 2. Determining the cost effectiveness of CMV PCR testing on DBS versus saliva