“…[1][2][3][4][5][6][7][8] Moreover, if audiometric studies are done, an additional 20% to 30% of such children are found to have some impairment of hearing.9 The earlier in pregnancy that maternal rubella occurs, the greater is the hazard to the fetus; thus, 50% or more of the children born of women contracting rubella during the first four weeks of pregnancy may have gross congenital anomalies. 10 Despite its usually mild, self-limited course in children, rubella frequently is a somewhat more severe disease in adults; and, in particular, it may constitute a problem in isolated communities and when groups of young adults are brought together in schools, other institutions, and in military installa¬ tions.11"17 At the US Naval Training Sta¬ tion at Great Lakes, 111, for example, there were 15,824 hospital admissions for rubella as compared to 111 admissions for measles during the period of 1955-1964.18 The reported occurrence of complications such as encephalitis and thrombocytopenic purpura, although extremely rare, and the more frequent occurrence of a mild arthritis simulating rheumatoid arthritis are further reasons for concern with rubella.11·19"23…”