Oral administration of a live-attenuated Bordetella bronchiseptica vaccine (Vanguard B Oral) induces protective immunity against challenge 7 days after vaccination in dogs

Objective: To evaluate the onset of immunity 7 days after administration of a live-attenuated Bordetella bronchiseptica (Bb) vaccine (Vanguard B Oral) in dogs. Methods: In a randomized, blinded, controlled study conducted at an animal research facility in 2022, forty 8-week-old Beagle puppies were randomly assigned to 2 groups (n = 20/group) and administered a single oral dose of either placebo or vaccine on day 0. On day 7 after vaccination, all dogs were challenged with aerosolized virulent Bb. Clinical observations were conducted twice on days 0 and 6 through 20 and once daily on days 1 through 5 and 21. Tympanic temperatures were measured twice on day 0 and once daily from days 1 through 21. Microplate agglutination titers were collected from all animals on days -12, 0, 6, and 21. Results: Coughing on 2 consecutive days occurred in 17 of 20 control dogs (85%) versus 4 of 20 vaccinates (20%). Vaccinated dogs also exhibited fewer coughing observation periods (3.2% vs 15.8%) and a shorter coughing duration of 2.4 days (95% CI, 1.0 to 3.7) than controls (5.5 days; 95% CI, 4.1 to 6.8). Total clinical scores were significantly lower in vaccinated (median, 15.0) dogs than in controls (median, 27.0) and remained significant when ocular and nasal discharge were excluded. Conclusions: The vaccine was considered safe, with only sporadic mild clinical signs. After challenge, vaccinated dogs demonstrated a significant reduction in coughing and other clinical signs. Clinical Relevance: Vanguard B Oral elicited a rapid onset of protective immunity against virulent Bb challenge as early as 7 days after vaccination.