DECHRA brand Avishield IB QX (infectious bursal disease virus, live) is a vaccine used to immunize chickens against avian infectious bronchitis caused by QX-like variants of the infectious bronchitis virus (IBV). Onset of immunity three weeks after vaccination, with the duration of immunity lasting for 10 weeks. Administered as a coarse spray, oculonasally, or in drinking water. An EU Authorised medicine.