AdvertisementWhat's In A Flu Name? H's And N's Tell A TaleMay 07, 2013Michaeleen DouclefffacebookEmailInfluenza covers it's shell with two types of accessories: the H spike, blue, and the N spike, red. Here the flu particle is sliced open to show its genetic material. (Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases)