Contaminant viruses in two live virus vaccines produced in chick cells

Abstract

Samples of yellow-fever vaccine prepared from homogenized chick embryos, and of an experimental measles vaccine prepared from chick embryo cells, have each been shown to contain a contaminant virus similar in properties to an avian leukosis virus. Young adult males injected with the yellow-fever vaccine did not develop neutralizing antibodies for Rous sarcoma virus.