MeaslesMeasles VaccineMeasles virusMeasles-Mumps-Rubella VaccineDisease OutbreaksImmunization ProgramsDisease NotificationMass VaccinationTravelPopulation SurveillancePan American Health OrganizationVaccinationAmericasImmunization ScheduleAntibodies, ViralIncidenceImmunoglobulin MWorld Health OrganizationSubacute Sclerosing PanencephalitisMorbillivirusAge DistributionUnited StatesAntigens, CD46MumpsRubellaMumps VaccineGenotypeHemagglutinins, ViralTime FactorsRubella Vaccine