The efficacy of an avian metapneumovirus vaccine applied simultaneously with infectious bronchitis and Newcastle disease virus vaccines to specific-pathogen-free chickens.

Avian metapneumovirus (aMPV), Newcastle disease virus (NDV), and infectious bronchitis virus (IBV) are important respiratory pathogens of chickens. To achieve early posthatch protection against all three diseases it would be helpful to deliver live aMPV, IBV, and NDV vaccines simultaneously at 1 day of age. However, previous work has indicated that the efficacy of aMPV vaccines may be affected when codelivered with IBV or NDV vaccines. The efficacy of an aMPV vaccine when codelivered to chickens in a trivalent combination with an NDV and an IBV vaccine was examined. The serological antibody response to the aMPV vaccine given with the IBV and NDV vaccine was significantly lower than when the aMPV vaccine was given alone. However, the aMPV vaccine did not affect the serological response to the IBV and NDV vaccines. Irrespective, the efficacy of the aMPV vaccine was not affected based on clinical signs postchallenge. This is the first report showing aMPV, IBV, and NDV vaccines can be codelivered without affecting the efficacy of the aMPV vaccine.