1 Department of Pediatrics, School of Medicine, University of Pennsylvania, Philadelphia, and the Division of Virus and Cell Biology Research, Merck Institute for Therapeutic Research, West Point, Pennsylvania
Merck (Benoit) strain rubella vaccine at attenuation level B in duck embryo cell culture afforded protection in all of 17 children who were intimately exposed to natural rubella in an epidemic which occurred 8 months following vaccination. Likewise, none of the children responding to Merck C and D level or HPV-77 vaccine became infected with rubella virus when exposed 10 months later to children who were given virus of low level attenuation (level A) and who were contagious to their contacts. Merck level B and HPV-77 vaccines prepared in duck cell cultures afforded high level persistent antibody without meaningful decline up to 33 and 12 months, respectively. Serial passage of the Merck strain virus in duck embryo cell culture resulted in further attenuation with slower and less antibody development initially, and in more rapid decline in antibody. Merck strain virus at attenuation level B and HPV-77 virus appeared to be optimal for use in children.
Submitted on January 21, 1969