Disclosed herein are nanoparticles containing MERS virus proteins in polymer structures, and compositions containing the nanoparticles formulated for administration as immunogenic compositions. Also provided herein are vector constructs encoding the proteins, and host cells containing the vector constructs. The disclosure also includes methods of making the nanoparticles and administering them to vertebrates, including methods of inducing immune responses to MERS that reduce or prevent infection by the virus.