A recent study by researchers at Monroe Carell Jr. Children’s Hospital at Vanderbilt and the Vanderbilt Center for Child Health Policy found that in Tennessee, most infants exposed to hepatitis C virus at the time of birth are not tested later to see if they acquired the virus. Over the past few years, hepatitis C virus rates among pregnant women have grown substantially—likely a consequence of the country’s opioid crisis. The increase has largely gone unnoticed.