Cytomegalovirus (CMV) complicates 1% of all pregnancies and results in 8,000 severe infections in U.S. children annually, resulting in hepatitis, neutropenia, brain damage, seizures, and vision and hearing loss. It is the leading nongenetic cause of infant hearing loss, accounting for 25% of all hearing loss, and causes more permanent disabilities in U.S. children than spina bifida or Down syndrome. Much like the rubella vaccine eliminated congenital rubella syndrome in this country, a vaccine that induces protection maternal immune responses in needed to protect against congential CMV. Thus, a team of DHVI researchers, led by Sallie Permar, MD, PhD, are working to identify the maternal immune responses that are required to protect against placental transmission of CMV in mother-infant cohort studies.