Long-term follow-up for immunity after monovalent or combined live measles, mumps, and rubella virus vaccines.

Antibody in human subjects persisted without substantial decline for 8 years after mumps vaccine (Jeryl Lynn), for 6 years after measles (Attenuvax), for 5 1/2 years after rubella vaccine (HPV-77 duck), for 5 years after measles-mumps-rubella and mumps-rubella combined vaccines, for 4 years after measles and rubella, and for 2 years after measles-mumps vaccines, the longest periods tested. Protective immunity against mumps illness persisted through the eighth year. The patterns for antibody following vaccination parallel those for natural infection and indicate that immunity will be lasting. Subclinical reinfection evidenced by antibody increase was commonly seen in persons who had been vaccinated, much as follows the natural infection.