U.S. President Joe Biden, who tested positive for COVID-19 while experiencing mild symptoms, sits at his desk in the White House residence in this handout photo obtained from President Biden's Twitter account on July 21, 2022. Courtesy Twitter President Biden@POTUS/Handout via REUTERS THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. THIS IMAGE WAS PROCESSED BY REUTERS TO ENHANCE QUALITY, AN UNPROCESSED VERSION HAS BEEN PROVIDED SEPARATELY.