A healthcare worker wearing personal protective equipment (PPE) places a Covid-19 swab test into a vial at a United Airlines testing sire inside San Francisco International Airport (SFO) in San Francisco, California, U.S., on Thursday, Jan. 9, 2021. California reported 459 daily virus deaths, the second-highest tally since the pandemic began, as the most-populous state continues to battle a surge of cases that has strained health-care facilities. Photographer: David Paul Morris/Bloomberg via Getty Images