Objective

Early vaccination of puppies is very desirable for owners especially when early socialization of puppies is expected. Although the immune system of dogs at 7 weeks is mature enough to respond to the vaccine stimulus, the presence of MDA can impede the development of protective immunity. Vanguard^TM 7 (Pfizer) is a core multivalent vaccine and the recommended vaccination schedule is a two-dose regimen with the first dose at 9 weeks of age and the final dose at 12 weeks of age. This study was designed to compare the serological responses of the viral fractions to administration of Vanguard^TM 7 vaccination at 9 and 12 weeks of age with an 'early finish' regimen, where pups were vaccinated at 7 and 10 weeks of age.

Method

Twenty-nine pups from vaccinated dams were randomly allotted into two treatment groups: 14 were allocated to T1 (vaccination at 9 and 12 weeks) and 15 were allocated to T2 (vaccination at 7 and 10 weeks). Blood samples were taken throughout the study and were analysed by virus neutralisation for antibodies to CDV, CAV and CPiV and by haemagglutination inhibition for antibodies to CPV. The antibody titers to CDV, CAV, CPV and CPiV in blood samples taken two weeks after the second vaccination and were compared using a mixed linear model to determine non-inferiority.

Results

The antibody titres for all four of the viral fractions of Vanguard^TM 7 in T2 were non-inferior to T1 i.e. the lower confidence limit for the log2 difference between treatments was greater (more positive) than -2: CDV (-1.5186), CAV (0.3474), CPV (-1.6684) and CPiV (-0.9305). Furthermore, categorization of animals according to their serological status at the start of the study demonstrated that even animals with high maternally derived antibody titres before vaccination developed protective titres post-vaccination in both treatment groups.

Conclusion

This study demonstrated that in pups born to fully vaccinated dams vaccination at 7 and 10 weeks of age provided protective serological responses to the viral fractions of Vanguard^TM 7 and that were non-inferior to the serological responses obtained when pups were vaccinated at 9 and 12 weeks of age.