Safety Testing of Rubella Virus Vaccine (Cendehill Strain): Preparation in Primary Rabbit Kidney Cells

THE CENDEHILL strain of rubella virus has been attenuated by serial passages in primary rabbit kidney (PRK) cells; details of its passage history and biological properties have been published. 1-3 After small scale clinical trials with various passage levels, the 51st passage was chosen for further evaluation. In subsequent trials, in larger groups of children and adults, this passage level appeared to possess all the properties desired for a live rubella virus vaccine, and so a large seed lot was prepared from it, tested for safety, and is being used to produce experimental batches of vaccine. The resulting vaccine, which has been evaluated in large scale clinical trials, corresponds to the 53rd passage level of the virus in PRK cells. The production of Cendehill rubella vaccine includes the same steps as the production of live measles vaccine, namely: preparation of tissue cultures, inoculation with seed virus, harvesting, pooling, clarification, and