Ms Grepps consults you about Aron, aged 13 months. Ms Grepps had seen a poster on MMR at the local maternal and child health centre and is concerned because of a story she had heard of a child who got measles after MMR. She also wonders whether MMR is really necessary as ‘measles, mumps and rubella do not seem very common these days and her mother says that natural immunity from catching these diseases gives better protection. Aron would get a Rubella injection in high school anyway’. Your records show that Aron had all the recommended vaccines at 2, 4 and 6 months.