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IN VITRO and in vivo properties of the attenuated Cendehill strain of rubella virus have been described previously. This strain has been attenuated by serial propagation in primary rabbit kidney cells. It is characterized by the production of an early cytopathic effect in rabbit cultures, by the formation of distinct plaques in RK13 cells, by loss of intranasal infectivity for the monkey, and by loss of immunogenicity for the rabbit after subcutaneous inoculation.1,2 Preliminary clinical trials with the Cendehill strain at the 21st and 51st passage levels have been reported previously.3-6Although attenuated virus at the 21st passage failed to spread from vaccinated subjects to susceptible contacts, the trials with this passage level were discontinued because mild but typical symptoms of rubella were observed in one of the vaccinees.4 We report here the results of several clinical trials in children and young adults, with the high-passage

Extract: High passage Cendehill strain of rubella virus, possesing in vivo and in vitro characteristics of an attenuated virus, was tested for efficacy in 28 seronegative infants, 3 to 23 months old. Thirteen seronegative infants received one subcutaneous injection of 0.5 ml of the vaccine preparation containg 103.7plaque-forming units (PFU) per ml. Fifteen seronegative infants served as controls for viral spread and were kept in intimate contact with the vaccinees for a period of 6 weeks.All thirteen vaccines developed high levels of hemagglutination-inhibiting antibodies, from 1/128 to 1/2048, confirming the immunogenicity of the vaccine. No clinical reactions were observed in the vaccinees. The fifteen contacts remained seronegative, indicating that no viral spread occurred from the vaccinees to the susceptible contacts.The present clinical trial provides evidence that high-passage Cendehill strain presents characteristics of immunogenicity, nonreactogenicity and noncommunicability, making it a prospective candidate for a live attenuated rubella virus vaccine.Speculation: When the results of preliminary immunization trials with the attenuated Cendehill strain of rubella virus are confirmed in larger groupt, this strain may meet all the criteria required for a safe and efficient immunizing agent against rubella.

Serum albumin and gamma-globulin increase rapidly during the development of the human fetus, whereas the alpha- and beta-globulins remain at a low level. The alpha- and beta- globulins rise appreciably and albumin decreases in maternal sera during pregnancy. The high gamma-globulin in newborn infants decreases markedly during the first month or two of life, whereas all of the other serum components rise. The view that the ingestion of colostrum maintains or raises the antibody level of infants is not supported by our findings.