Comparison of antibody responses after vaccination with two inactivated rabies vaccines

Thirty laboratory dogs were randomly assigned to two groups (A and B) of 15 dogs and subcutaneously vaccinated with a single dose of one of two commercially available monovalent inactivated rabies vaccines: RABISIN1 (Merial, France) (group A) and NOBIVAC2 Rabies (Intervet International) (group B). Rabies antibodies were measured over a period of 4 months using the fluorescent antibody virus neutralization (FAVN) test. The two vaccines performed differently in terms of magnitude and persistence of rabies antibodies titers in dogs. Two weeks after vaccination, average rabies antibody titers peaked at 2.53 IU/mL (range, 0.17–13.77 IU/mL) and 1.26 IU/mL (range, 0.50–4.56 IU/mL) in groups A and B dogs, respectively. The average FAVN antibody titres against rabies on D28, D56, D84, D112 and D120 were significantly higher in group A than in group B. Although all dogs from group B serologically responded to vaccination, the proportion of dogs with antibody titres ≥0.5 IU/mL dropped significantly after D28 and was statistically significantly lower on D56, D84 and D112 compared to group A dogs. In conclusion, in the context of international trade, the choice of the vaccine and the timing of blood tests are critical factors in achieving successful serological test results after rabies vaccination. RABISIN induces high and sustained antibody titres against rabies, increasing the flexibility for the time of blood sampling after primo-vaccination.