On Friday, Biden said in an interview with ABC News that he was sick and felt terrible during the debate.
On June 25, Biden woke up with a cold, held a brief rehearsal of the debate with his staff, and then rested all day, Politico reported on Friday, citing five sources. His COVID-19 tests reportedly came back negative. The next day, aides tried to catch up with the debate, with preparations continuing into Thursday morning, the report read. Some aides believe the increased rehearsals further exhausted Biden, the sources told the news website.
Biden appeared confused and incoherent throughout his first debate with Republican frontrunner Donald Trump last Thursday, reinforcing rather than refuting ongoing concerns about his cognitive abilities at age 81. His poor performance has led some Democratic politicians, donors, and other supporters to call for his removal as a candidate.
The US presidential election is slated for November. The main contenders expected on the ballot are Biden and Trump, who have both won enough delegates' votes to be their respective Democratic and Republican parties' presumptive nominees. Trump and Biden are set to debate again on September 10.