Comparison of adjuvants for an inactivated infectious coryza vaccine

Differently formulated inactivated infectious coryza vaccines were administered to 6-week-old chickens as a single dose of 10(8) colony-forming units of Haemophilus paragallinarum HP31. After 3 weeks, all chickens were challenged by intrasinus inoculation of HP31. Two vaccines, one containing an aluminum-hydroxide adjuvant and the other a combined aluminum-hydroxide + mineral-oil adjuvant, gave the best protection (means of 80% and 90%, respectively). Two vaccines that contained mineral oil as the sole adjuvant gave less protection (50% and 35%). The Quil A vaccine gave no significant protection. Granulomatous swellings developed at the site of injection in birds given mineral-oil adjuvant but not in those that received other adjuvants.