 Biden's doctor says his symptoms have improved since Wednesday when he first tested positive for COVID. But while Biden may be recovering medically, politically, his campaign is on shaky ground. Nearly three dozen lawmakers and his own party have called on Biden to end his candidacy for president. Still, Biden has dug in. In a statement he released Friday, he said he would be back on the campaign trail next week. Deepa Shivaram, NPR News, Rehoboth Beach, Delaware.