A new test for the coronavirus that has seen US President Joe Biden, who contracted Covid about ten days ago, come back positive after four previous tests had instead returned negative results. Biden has therefore not yet fully recovered from the infection, which in any case has not given him any major symptoms. Her doctor said it was a “relapse” and the test, which temporarily signaled negative, had been affected by taking a drug, Paxlovid, which lowers viral loads and therefore quickly leads to negative test results despite an ongoing infection can. Biden said he will go back into isolation until fully healed.