How could scientists race out COVID-19 vaccines so fast without cutting corners? A head start helped. Over a decade of behind-the-scenes research had new vaccine technology poised for a challenge just as the coronavirus erupted. The two U.S. frontrunners are made with a genetic code called messenger RNA. They target the spike protein coating the virus. Earlier research from the University of Pennsylvania and National Institutes of Health laid the groundwork for unusually rapid development and testing of those shots. U.S. regulators are set to decide this month whether to allow emergency use, paving the way for rationed shots.