Joe Biden has again tested positive for novel coronavirus, in a rare case of “rebound” following treatment with an anti-viral drug. This comes nearly three days after he had tested negative and was cleared to exit the isolation. The development was confirmed by the White House. Joe Biden has again tested positive for novel coronavirus, in a rare case of “rebound” following treatment with an anti-viral drug. This comes nearly three days after he had tested negative and was cleared to exit the isolation. The development was confirmed by the White House.