Provided herein are non-naturally occurring, broadly reactive antigens derived from influenza viruses or avian infectious bronchitis virus (IBV) that are immunogenic and capable of eliciting a broadly reactive immune response, e.g., a broadly reactive neutralizing antibody response, directed against influenza virus antigens or IBV antigens following introduction into a subject. Also provided are non-naturally, broadly reactive immunogens, vaccines, virus-like particles (VLPs) and compositions comprising the immunogens and vaccines. Methods of generating an immune response in a human or non-human subject by administering the immunogens, vaccines, VLPs, or compositions thereof are provided. In particular, the immunogens comprise broadly reactive hemagglutinin (HA) protein antigens of influenza virus strains, such as H1, H2, H3, H5, or H7, or of IBV. The immunogens also comprise broadly reactive viral neuraminidase (NA) protein antigens.