Antibody response following measles-mumps-rubella vaccine under conditions of customary use

A study of 301 children who had been immunized two to 19 months previously with measles, mumps, and rubella (MMR) vaccine at 36 different sites in San Antonio, Tex, including physicians' offices and clinics, revealed that 99.7% had antibody against rubella and 98.3% had antibody against measles and mumps. None of the 49 infants who were tested prior to receipt of MMR vaccine had antibody against any of these viruses, indicating that the antibody found after immunization was unlikely to be due to false-positive results. The lack of antibody in these infants confirmed that there had not been a significant number of cases of these diseases that could contribute to the high frequency of antibody found after immunization. A single dose of MMR vaccine administered under customary conditions appears to be an effective method of conferring immunity against these diseases.