RUBELLA is a mild childhood disease for which vaccine would not be considered if it were not for its effect on the fetus in utero. Ten to twenty thousand malformed children have been estimated to have been born in the United States as a direct result of the 1963 to 64 rubella epidemic. A vaccine for rubella became possible following the isolation of the virus in 1962.1,2 Subsequently, Parkman et al3 and Meyer et al4 demonstrated that the virus could be attenuated by serial passage 77 times through African green monkey kidney (GMK) cell culture. This attenuated strain has been shown to produce a good antibody response in as high as 90% of vaccinees without causing rash disease. Protection in a few children against experimental challenge has been reported,5 but the efficacy of live attenuated rubella vaccine in prevention of natural disease had not been evaluated