Fig. 7 Efficacy of the rH120 and rH120-S1/YZ vaccines. (A) Percent survival of the vaccinated chickens challenged with the QX-like IBV rIBYZ strain during the 14-day observation period. No mortality was observed in the chickens vaccinated with the rH120-S1/YZ strain. (B) Gross lesions observed on the kidneys of the vaccinated chickens challenged with the rIBYZ strain at 5 or 7 dpc. (C) The mean antibody OD value at 7, 14, 21, and 28 dpv. All data are presented as the mean ± standard error of the mean (SEM).