“…In the case of influenza, the structure-guided design of effective HA immunogens coupled with structural determination by X-ray crystallography and cryo-EM indicate a potential paradigm shift in how vaccine immunogen design will be approached in the future [ 10 , 11 , 14 , 16 ]. There is an increasing recognition of the power of cryo-EM as a structural technique, as it has aided in the structural determination of influenza epitopes in the context of influenza viruses, designed antigens, immune complexes, chimeric HA molecules, and vaccine nanoparticles [ 4 , 11 , 16 , 39 , 45 , 46 , 106 , 124 ].…”