title: [Observation on the protective effects of live measles vaccine in various number of years after the first immunization].
mesh_terms: D002675:Child, Preschool; D006801:Humans; D007117:Immunization, Secondary; D007223:Infant; D008457:Measles / Q000517:prevention & control*; D008458:Measles Vaccine; D013997:Time Factors
chemical_list: D008458:Measles Vaccine