Considerable immunity gaps in respect of mumps and rubella (German measles) of up to 30% among pupils of the prepuberty age are the requisite arguments in favour of the need for vaccination measures. Combined protective vaccination with live attenuated measles-mumps-rubella vaccine without preceding laboratory tests is recommended for practical reasons and economy. No side effects have been seen on renewed protective vaccination with live attenuated measles vaccine in case of already existent natural immunity. A booster effect can be demonstrated in vaccinated persons with low or borderline antibody levels. Revaccination from the 6th year of life onwards is recommended and advocated to close existing vaccination and immunity gaps.