Updates to adult and child immunization schedules are issued for 2018. Changes for adults include recommending a third dose of a mumps-containing vaccine for at-risk people during a mumps outbreak. A newer recombinant zoster vaccine is preferred for adults 50 years and older, rather than the previous live zoster vaccine. For children, the update explains that a vaccine series does not need to be restarted even if time has elapsed between doses. Vaccines given within four days of the minimum age are considered valid, but if given five or more days earlier than the minimum age, they are invalid and need repeat dosing. The new schedules, from the Centers for Disease Control and Prevention, are available at http://www.cdc.gov/vaccines/schedules/hcp.