Final answer:
Cytomegalovirus (CMV) is the most common congenital viral infection in newborns and can lead to serious health issues, although most infected infants do not show symptoms or long-term effects.
Step-by-step explanation:
The most common congenital viral infection in newborns is caused by Cytomegalovirus (CMV), also known as human herpesvirus 5 (HHV-5). This virus is prevalent with a high infection rate among the human population, with about 50% of people in the US being infected by adulthood. While the majority of CMV infections are asymptomatic, the virus can cause serious issues in immunocompromised individuals, such as AIDS patients, transplant recipients, and neonates. Among newborns, congenital CMV is a significant concern as it can lead to severe and potentially permanent health issues, such as hearing loss, vision impairment, and developmental disabilities. However, approximately 80% of infected infants never show symptoms or develop long-term problems. CMV is diagnosed during pregnancy using serology and is part of the prenatal TORCH screening.