The challenges in developing effective canine infectious respiratory disease vaccines

Objectives Canine infectious respiratory disease ( CIRD ) is a disease of multifactorial aetiology, where multiple pathogens act sequentially or synergistically to cause disease. It is common within large dog populations, such as those in re‐homing or training kennels. Vaccines are vital in its management of CIRD , but they often fail to prevent disease. Recently, a number of novel pathogens have been identified in CIRD outbreaks and represent new targets for vaccination. Key findings Innate immune responses provide a vital first line of defence against the infectious agents involved in the development of CIRD . Once breeched, adaptive mucosal immunity is necessary to prevent infection and limit spread. Current vaccines target only a few of the agents involved in CIRD . Evidence, from the limited amount of published data, indicates that although vaccinating against these agents reduces infection rates, duration of shedding and severity of disease, it does not induce sterilising immunity; and this has important consequences for the management of the disease, and the future of CIRD vaccine development. Summary In the process of considering the development of novel CIRD vaccines, this paper focuses on the immunological mechanisms that provide protection for the respiratory tract, the current recommendations for canine vaccination, and the challenges surrounding existing CIRD vaccines, and their future development.