Phosprenyl increases the effectiveness of dogs immunization against canine distemper: a single-center blind, placebo-controlled study

For objective reasons, imported vaccines for dogs are now practically non available in our country, which has dictated the necessity to increase requirements for domestic vaccines. Most Russian vaccines are quite effective and safe, but they are not free from disadvantages, one of which is the impossibility of subcutaneous use due to the aluminum hydroxide, present in vaccines as an adjuvant. This leads to the search for new adjuvants that can not only induce innate immune responses necessary for subsequent activation of the adaptive immune response, but should also fully meet safety requirements. One of such adjuvants may be Phosprenyl (PP), which is used in veterinary medicine as an antiviral agent with an immunomodulatory effect. The purpose of this work was to study the adjuvant effects of PP for vaccination against canine distemper. For a single-center blind placebo-controlled study, 24 dogs aged 2.5 months were selected, which were randomly divided into 2 equak groups, experimental and control. The first immunization of all dogs was carried out using the Multican-4 vaccine, while Multican-8 was used for the second. The dogs of the experimental group were additionally injected with PP at a dose of 0.3 ml / kg of weight subcutaneously - simultaneously with the first and second vaccinations. Already after the first vaccination inoculation of PP led to a significant increase in the titer of specific antibodies against the canine distemper virus (CDV). The level of antibodies was determined at various times up to 255 days after vaccination. It was found that in dogs of the experimental group, during the entire experiment, the concentration of antibodies against CDV significantly exceeded the level of antibodies in control animals. Thus, the combined use of PP with the Multican-4 and Multican-8 vaccines contributed to an increase in the intensity of vaccine immunity against CDV and prolongation of its protective effect.