NEW YORK (AP) — A federal vaccine advisory committee voted Friday to end a longstanding recommendation that all U.S. babies get the hepatitis B vaccine on the day they’re born. For decades, the government has advised that all babies be vaccinated against the liver infection right after birth, which has prevented thousands of illnesses. However, U.S. Health Secretary Robert F. Kennedy Jr.’s committee now recommends that the birth dose be given only to babies whose mothers test positive for the virus or whose infection status is unknown. For other infants, it will be up to parents and their doctors to decide if the birth dose is necessary.

The new guidelines suggest that vaccinations against hepatitis B for those not receiving the birth dose should commence no earlier than two months of age. Some committee members argued that most babies are at a low risk for infection and that previous studies assessing possible vaccine harms were inadequate to identify long-term complications. This decision has raised concerns among many medical groups who fear that a greater number of children could become infected as a result. Jim O’Neill, the acting director of the Centers for Disease Control and Prevention, will decide later whether to accept the committee’s recommendation.