g, which represents a substantial challenge to IBV control [1], [6]. In this study, we detected viral RNA in the oral and cloacal swabs isolated from infected chickens at 7, 14, 18, 22, and 26 dpi by real-time PCR. Compared with rH120 and rIBYZ, the viral load in both the oral and cloacal swabs of the rH120-S1/YZ group at different time p