The duration of immunity to an inactivated adjuvanted canine parvovirus vaccine. A 52 and 64 week postvaccination challenge study.

Dogs were successfully isolated for a period of either 52 or 64 weeks following vaccination with an inactivated, adjuvanted canine parvovirus-2 vaccine. Antibody persisted in all ten vaccinated dogs, although in one case by 52 weeks postvaccination only virus neutralizing antibody, and not hemagglutination-inhibiting antibody, could be detected. Sentinel unvaccinated dogs housed alongside the vaccinated dogs throughout the study remained free of canine parvovirus-2 antibody until challenged. Upon oral challenge with canine parvovirus-2 infected material all unvaccinated dogs developed one or more signs of canine parvovirus-2 disease, shed virus and developed antibody. None of the vaccinated dogs became overtly sick. Of the five vaccinated dogs challenged 52 weeks after vaccination, three shed virus and one showed a significant rise in antibody. At 64 weeks after vaccination only one of the five challenged dogs shed virus and showed a boost in antibody titer.