The Centers for Disease Control and Prevention's (CDC) Advisory Committee on Immunization Practices (ACIP), recently reconstituted under Health and Human Services Secretary Robert F. Kennedy Jr., held a contentious meeting discussing changes to childhood vaccine guidelines. The panel voted to remove the recommendation for the combined MMRV vaccine for children under four and delayed a vote on postponing the newborn hepatitis B vaccine. Discussions highlighted concerns about data adequacy and safety, casting uncertainty on immunization policy and public health implications amid internal CDC discord.