Comparison of vaccine efficacy for different antigen delivery systems for infectious pancreatic necrosis virus vaccines in Atlantic salmon (Salmo salar L.) in a cohabitation challenge model

► Inactivated whole viral (IWV) vaccines conferred good protection against IPN. ► Nanoparticle, sub-unit recombinant vaccines and DNA vaccine are inferior to IWV. ► Antibody levels were different between vaccine formulations. ► Highest antibody levels gave highest level of protection. ► Prevention of tissue damage was linked to protection against mortality.