A workgroup (WG) of the Center for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) has been tasked with gathering data for members of the full panel regarding the efficacy and safety of the timing and order of child vaccines and the safety of their ingredients. The information will be used by the ACIP members appointed by U.S. Health and Human Services Secretary (HHS) Robert F. Kennedy, Jr. for the purpose of making recommendations to the child and adolescent immunization schedule.