A vital CDC advisory group is reevaluating the timing of the hepatitis B vaccine for infants. Currently administered within hours of birth, the proposed change would delay the first dose until babies are at least one month old, reflecting a potential shift in public health policy.

Less than a month into her tenure, CDC Director Susan Monarez has left her position, federal officials confirm. The swift departure raises questions about the direction and leadership of the nation’s top public health agency.