President Joe Biden is now testing negative for COVID-19 and his symptoms have resolved, according to a letter from his doctor, Kevin O'Connor, released Tuesday. Related video above: Biden will meet with Netanyahu on Thursday in WashingtonBiden called into the Wilmington, Delaware, headquarters of his former campaign during a visit by Vice President Kamala Harris, whose bid for the White House has been endorsed by Biden. The president sought to pep up the staff, urging them to give “every bit” of their “heart and soul" to Harris. Biden also vowed to be “out on the road” campaigning for his vice president.“If I didn’t have COVID, I’d be standing there with you," said Biden, whose voice sounded a touch gravelly.The president was last seen in public late Wednesday after arriving at a U.S. air base in Dover, Delaware, after testing positive for COVID-19 while campaigning in Las Vegas earlier in the day. He then motorcaded to his vacation home in Rehoboth Beach, Delaware. The White House says Biden plans to return to the White House on Tuesday afternoon.Biden’s physician, Dr. Kevin O’Connor, said that the president had completed his 10th dose of the COVID-fighting medication Paxlovid on Monday morning and continued to perform all of his presidential duties. The White House said Biden received separate briefings on Monday from homeland security adviser Liz Sherwood-Randall and national security adviser Jake Sullivan. Both briefings were conducted virtually.On Tuesday, Biden announced that he will address the nation on Wednesday to discuss his decision to end his candidacy. Biden plans to meet with Israeli Prime Minister Benjamin Netanyahu at the White House Thursday, according to a U.S. official who spoke on condition of anonymity ahead of the White House announcement.Biden also plans to meet at the White House later this week with the families of Americans who are still being held hostage in Gaza, according to a statement from the group of families who met privately with Sullivan earlier Monday.It would be the second time that Biden has met with the families. The families again publicly urged Israel and Hamas to come to an agreement on a cease-fire deal that would release their loved ones. Biden in late May proposed a three-phased deal aimed at returning remaining hostages taken by Hamas in the Oct. 7 attack on Israel and could potentially lead to a permanent truce to end the nine-month war in Gaza.“We’re going to keep working to an end to the war in Gaza," Biden said during his call-in to the campaign headquarters. "I’ll be working really closely with the Israelis and with the Palestinians to try to work out how we can get the Gaza war to end, and Middle East peace, and get all those hostages home. I think we’re on the verge of being able to do that.”