A SEVERE epidemic of rubella appeared throughout a large part of the United States early in 1964, resulting in infection of many pregnant women.1,2During the last months of 1964 and early in 1965 numerous infants were born with congenital abnormalities, including cataracts, congenital heart disease, thrombocytopenia, hepatosplenomegaly, bone lesions, and central nervous system damage.3,4A causal relationship between maternal rubella and congenital abnormalities had been established over the past 20 years by clinical and epidemiologic observation.5-9More recently, the relationship has been substantiated by serological studies of newborn infants with abnormalities10-12as well as by the frequent recovery of rubella virus from these same infants.3,4,13,14The incidence of congenital abnormalities due to the 1964 rubella epidemic is as yet incompletely assessed, but early estimates have ranged between 0.3% to 4.0% of infants in utero during the epidemic.4,15,16 This current experience, in addition to