Efficacy of a Modified-Live Virus Combination Vaccine (CDV, CAV, CPV, CPiV), CanigenTM DHPPi, in Puppies Vaccinated at Six Weeks of Age.

During their early life, puppies are protected against infectious agents with the presence of maternal derived antibodies (MDA). Vaccination is recommended to start as soon as the levels of MDA begin to wane to ensure that the puppy's immune system can respond effectively to the vaccines and develop active immunity against diseases. Two studies were designed to assess the efficacy of the CanigenTM DHPPi vaccine in puppies from 6 weeks of age. The studies comprised two parts: the efficacy assessment of the Canine Parainfluenza Virus (CPiV) vaccine component against a virulent challenge with CPiV (Experiment A) and an immunogenicity assessment of Canine Distemper Virus (CDV), Canine Adenovirus (CAV-2), and Canine Parvovirus (CPV-2) vaccine components (Experiment B). In Experiment A, twelve puppies were immunized with two injections of CanigenTM DHPPi (at minimum titer) two weeks apart and twelve control puppies received the vaccine diluent. All animals were challenged with a virulent, heterologous CPiV strain two weeks after the second vaccination. Vaccinated puppies exhibited a significant reduction in nasal viral shedding compared to the control group. Clinical signs of respiratory disease were mild and transient in both groups. In Experiment B, six puppies were immunized with two injections of CanigenTM DHPPi (at minimum titer) two weeks apart. A follow-up of the seroneutralizing antibodies titers against the CDV, CAV-2 and CPV-2 vaccine components was performed in order to assess the efficacy on the serological response basis. After the first vaccine injection, all the puppies seroconverted and presented seroneutralizing antibody titers reaching a protective thresholds against CDV (≥100.82), CAV-2 and CAV-1 (≥100.82), CPV-2 and CPV-2c (≥101.8). After the second vaccine injection, a more robust immune response was observed and the seroneutralizing antibody titers remained high until 4 weeks post vaccination for those three vaccine components. In both experiments (A and B), all vaccinated animals remained in good health, with no adverse reactions recorded during the vaccination phase. As a conclusion, the efficacy of the CanigenTM DHPPi vaccine was demonstrated when administered in dogs from 6 weeks of age. These results fully support the interest of an early vaccination in such young puppies followed by the recommended vaccination scheme.