Pilot Studies on Recombinant Cold-Adapted Live Type A and B Influenza Virus Vaccines

Abstract

Recombinant live attenuated type A and B influenza virus vaccines derived from standardized cold-adapted parent strains were given singly and in combination to volunteers. The vaccine viruses were well tolerated, functioned as good antigens, and failed to spread to intimate household contacts. Thirty-nine isolates that were recovered after a single passage in humans appeared genetically stable. The results of histopathologic studies in ferrets encourage development of an animal model for attenuation of the virus.