The chief executive of Pfizer said on Friday that the company would not apply for emergency authorization of its coronavirus vaccine before the third week of November, ruling out President Trump’s assertion that a vaccine would be ready before Election Day on Nov. 3.
In a statement posted to the company website, the chief executive, Dr. Albert Bourla, said that although Pfizer could have preliminary numbers by the end of October about whether the vaccine works, it would still need to collect safety and manufacturing data that will stretch the timeline to at least the third week of November.
Close watchers of the vaccine race had already known that Pfizer wouldn’t be able to meet the requirements of the Food and Drug Administration by the end of this month. But Friday’s announcement represents a shift in tone for the company and its leader, who has repeatedly emphasized the month of October in interviews and public appearances.
In doing so, the company had aligned its messaging with that of the president, who has made no secret of his desire for an approved vaccine before the election. He has even singled out the company by name and said he had talked to Dr. Bourla, whom he called a “great guy.”
Some scientists applauded Pfizer’s announcement.
“This is good, really good,” said Dr. Eric Topol, a clinical trial expert at Scripps Research in San Diego who was one of 60 public health officials and others in the medical community who signed a letter to Pfizer urging it not to rush its vaccine.
He said company officials had assured him that a vaccine would most likely not be authorized before the election, but the letter Friday is “even more solid about their not being part of any political machinations.”
Dr. Bourla has pushed back against any suggestion that Pfizer’s vaccine timeline was politically motivated. In September, Pfizer was the driving force behind a pledge by nine vaccine companies to “stand with science” and not put forward anything that had not been properly vetted. Earlier this month, he published an open letter to employees that said he “would never succumb to political pressure” and expressing disappointment that “we find ourselves in the crucible of the U.S. presidential election.”
Pfizer is one of four companies testing a coronavirus vaccine in late-stage clinical trials in the United States, and it has been the most aggressive in its timeline estimates. Moderna, AstraZeneca and Johnson & Johnson have said that later in the year is more likely, matching the predictions of federal health officials. (AstraZeneca and Johnson & Johnson’s trials have been paused for potential safety concerns, which could further delay their outcomes.)
In interviews, Mr. Bourla has said that he expects a “conclusive readout” by late October, with an application for emergency authorization that could be filed “immediately.”
Pfizer’s trial of 44,000 volunteers tests the vaccine by giving one group the vaccine, another group the placebo, and waiting until a certain number of people become infected with the