Newborn Screening for Congenital Cytomegalovirus in Canada

Abstract

What Is the Issue Congenital cytomegalovirus (cCMV) infection is a leading cause of childhood hearing loss. It is estimated that 85% to 90% of newborns infected with cCMV will not show any symptoms at birth. Of those newborns with cCMV infection who are asymptomatic at birth, 10% to 15% will go on to develop long-term symptoms, including vision loss, hearing loss, and developmental delays. What Did We Do? This brief provides a summary about newborn screening for cCMV in Canada, including whether screening is available for cCMV in each province and territory, and if so, whether screening is universal or targeted using publicly available information. What Did We Find? Currently in Canada, 4 provinces (Alberta, Saskatchewan, Manitoba, Ontario) have or are implementing universal newborn screening for cCMV. Three provinces (British Columbia, New Brunswick, Nova Scotia) have province-wide targeted screening programs that offer cCMV testing to newborns who fail newborn hearing tests or who have suspected cCMV as identified by a clinician. Current clinical guidance and practice remain mixed on whether targeted or universal newborn screening is recommended, with each having a different distribution of benefits and harms. cCMV infections can be detected using blood, urine, or saliva tests. Most universal newborn screening programs use dried blood spot tests, which are likely to produce false-negative results; saliva tests have a lower number of false-negative results but can result in a higher number of false-positives. Some programs recommend additional testing using a different method (either saliva or urine) after an initial positive test as a validation. What Does This Mean? As both universal and targeted newborn screening programs have been adopted by several jurisdictions in Canada, there is wide recognition that cCMV infection is a serious health issue and that early detection is important. Moreover, there is an opportunity to generate data and evidence about test performance and program impact over time that could support future decision-making. As evidence and new test and treatment options become available, such data will help to inform the type of newborn screening approach used for cCMV.