The occurrence of Venezuelan equine encephalomyelitis in at least 24 unimmunized laboratory workers has indicated the desirability of a human vaccine.1 In 1949 the Veterinary Division, Army Medical Service Graduate School, reported the development for human use of a highly purified vaccine prepared with formaldehyde. Inoculated volunteers showed excellent immunologic response.2 A review of the existing literature and communication with the Army Medical School revealed that viremia had never been found after the administration of any of the three equine encephalomyelitis vaccines.3 The purpose of this paper is to report 14 cases of Venezuelan equine encephalomyelitis occurring in humans after inoculation with the vaccine.
METHOD OF STUDY
Four lots of the encephalomyelitis vaccine furnished by the Army Medical School were used. They were prepared in this manner: Lots 1, 2, and 3 were prepared from chick embryos infected with a strain of Venezuelan equine encephalomyelitis virus isolated