A patient receives a shot of the Moderna COVID-19 vaccine next to a guidelines sign at a CVS Pharmacy branch in Los Angeles. More than 27 million Americans fully vaccinated against the coronavirus will have to keep waiting for guidance from U.S. health officials for what they should and shouldn't do. The Biden administration said Friday it's focused on getting the guidance right and accommodating emerging science. (AP Photo/Marcio Jose Sanchez, File)