Immunogenicity and Safety of an Inactivated Vaccine for the Prevention of Rhinotracheitis, Caliciviral Disease, and Panleukopenia in Cats

An inactivated vaccine for the prevention of feline viral rhinotracheitis (FVR), caliciviral disease, and panleukopenia has been developed. The efficacy of this vaccine for protection against FVR and caliciviral disease was assessed by vaccination of 41 cats and challenge of immunity with rrither FVR virus or feline calicivirus (FCV), strain 225. All vaccinates cats developed serum neutralizing (SN) antibody (mean SN50 1:45.5) to FVR virus, and 95% developed antibody (mean SN50 1:8.1) to FCV, strain 255. Following FVR challenge, the mean cumulative score of clinical signs was 1.1 for vaccinated cats versus 22.2 for controls. Following FCV challenge, the mean scores were 2.7 for vaccinated and 17.5 for controls. Immunogenicity of the panleukopenia fraction was demonstrated by the development of neutralizing antibody titers > 1:8 in all 21 vaccinates that were tested.