Human clinical trials have begun on a new vaccine candidate that may protect against not only SARS-CoV-2, the virus that causes COVID-19, but against at least two of the variants emerging around the world. The development of this new vaccine was guided by structural information on the virus obtained at the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility at DOE’s Argonne National Laboratory, and other light sources.