Pfizer is one of four companies with large, late-stage clinical trials underway in the United States.Credit…Brendan Mcdermid/Reuters After weeks of dangling the possibility of early coronavirus vaccine results by October, Pfizer’s chief executive said Tuesday that would now be nearly impossible. The announcement, by Dr. Albert Bourla, came on the same day that Pfizer announced third-quarter earnings, and all but ruled out the possibility of early results before the presidential election next Tuesday. President Trump had long sought to tie the possibility of positive vaccine news to his own prospects for re-election. In a call with investors on Tuesday, Dr. Bourla was pushed by Wall Street analysts to be more specific about when the company would have an idea of whether early results could show whether its vaccine is effective, and how much detail the company would provide when it is. Pfizer is one of four companies with large, […]