President Joe Biden is in full swing with top aides this weekend to return to the campaign trail in a last-ditch effort to salvage his re-election bid, despite anxious calls from fellow Democrats for him to step aside. Mr. Biden has been quarantined at his beach house in Delaware after testing positive for the novel coronavirus on Wednesday, while calls from Democrats in the House and Senate for him to drop out have grown unabated. Those closest to Mr. Biden say his determination to run for re-election has hardened in recent days, despite constant persuasion from some senior members of the party. However, that has not quelled rumours in Washington that he will announce his withdrawal at the weekend, and even Mr. Biden's longtime allies believe his re-election bid has reached a dead end. Amid speculation that his campaign was nearing its end, Mr. Biden himself issued a statement vowing to resume campaigning next week. Vice-President Harris also told top Democratic gifters that Mr. Biden still had a chance of winning. Jennifer O'Malley Dillon, chairperson of Mr. Biden's campaign, said in a rare television interview that he was "more determined than ever".