Just read the latest pediatrics in review article on CMV and this is what I learned. Since I never remember numbers, I’m going to present lots of numbers here to put things in perspective and also so I can look back to reference the numbers in the future.
In developed countries, more than 90% of teens have been exposed to CMV, and more than 95% of young adults show signs of past CMV infection in their blood. Prevalence (how many people have this disease now, versus incidence which is how many people get this disease per year) of congenital CMV (cCMV) 0.5 to 1% in developed countries, and 1-5% in developing countries. Of the babies with congenital CMV (cCMV), only 25% are from primary maternal infections, first time infection in the mom while pregnant. The other 75% of the time the infections are thought to be reactivation of prior infection or infection with a new strain of CMV. Post-natally, CMV can also be transmitted through the breast milk but only causes problems in the baby less than 32 weeks or weighing less than 1500 grams.
Only 10% of the babies are symptomatic. Symptoms range from petechiae (purple polka dot rash), jaundice (yellow discoloration due to high level of bilirubin), enlarged spleen and liver, chorioretinitis/optic atrophy (eye problems… and that’s all I understand it as mostly, so I’m not dumbing it down, I’m really just passing on what’s in my brain), microcephaly (small head), seizures, high liver enzymes (mostly AST), low platelets, and high bilirubin levels.
Of the babies who have symptoms, 50% have long lasting problems from it, 50% of which is hearing loss. Hearing loss also developed in 10% of the babies born without symptoms of CMV disease. cCMV can be treated with an anti-viral medication called valganciclovir. The side effects from the mediation can be pretty severe, such as myelosuppression, essentially lowering the body’s own immune system, the treatment is reserved for babies with severe neurologic involvement.
The usual test to check for CMV in a baby is PCR assay on the urine. Babies are not routinely screened for CMV, except in Utah. Connecticut and Illinois tried, but the legislation did not pass (http://www.vbivaccines.com/wire/universal-cmv-screening-of-newborns-faces-systemic-challenges/).
Anyway, the take home message is that CMV is common, congenital CMV can happen even if the mom had no history of CMV infection during pregnancy. Hearing loss can occur in a child who did not have personal or maternal history of CMV disease.