Washington, Aug 10 : US President Joe Biden coughed throughout his remarks at a bill-signing event outside the White House. Biden, who ended isolation on Sunday after testing negative for Covid-19 in a rebound case, halted the prepared speech multiple times behind the podium on the South Lawn, Xinhua news agency reported. "I'm going to take another sip of water," he told the audience on Tuesday morning while struggling to clear his throat. The White House issued a statement after the event, saying that the President tested negative for the coronavirus on Monday and Tuesday morning. Cough is one of the symptoms that those who experience post-Covid conditions commonly report, according to researchers. Fully vaccinated and twice boosted, Biden first tested positive for Covid-19 on July 21, leading to days of isolation and treatment at the White House before receiving negative test results. He tested positive again on July 30 and had a mild cough but didn't resume treatment. /IANS