Written documentation of vaccination includes vaccine type, date, administration details, and clinic stamp; documentation may be in a medical record of an official immunization record (e.g., “yellow shot card”).  Children should have two documented doses of MMR (or MMRV) administered after age 12 months and separated by at least 28 days.  Adults should have at least one documented lifetime dose of a live-measles vaccine (like MMR or MMRV).  Adults should have two documented lifetime doses of live-measles vaccine if they are international travelers, students, healthcare workers, household contacts of immune-compromised people, or otherwise considered at higher risk of measles exposure.