President Trump on Saturday baselessly accused the Food and Drug Administration of impeding enrollment in clinical trials for coronavirus vaccines and therapeutics for political reasons, as he broadened and escalated his attacks on administration scientists.

“The deep state, or whoever, over at the FDA is making it very difficult for drug companies to get people in order to test the vaccines and therapeutics,” he said on Twitter. “Obviously, they are hoping to delay the answer until after November 3rd. Must focus on speed, and saving lives!” He tagged FDA Commissioner Stephen Hahn in the tweet.

A second tweet reiterated Trump’s displeasure that the agency in June withdrew emergency authorization for hydroxychloroquine, an anti-malaria drug that is unproved as a treatment for covid-19, the disease caused by the novel coronavirus. It has been identified as potentially risky for covid-19 patients, and yet the president still touts its use.

The tweets represent a new turn in the president’s ongoing attacks on administration scientists. For months, he has undercut Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, for citing evidence that contradicts the president’s opinions on issues including the wearing of masks and whether in-person learning and the football season should resume. Several weeks ago, Trump described White House coronavirus task force coordinator Deborah Birx as “pathetic” after she said the virus was “extraordinarily widespread.”

Until recently, Trump had praised the FDA for moving quickly on coronavirus treatments and vaccines. But on Wednesday, he claimed the FDA was delaying authorizing convalescent plasma, an old treatment used for other infectious diseases but the effectiveness of which for covid-19 has not been proved. “You have lot of people over there that don’t want to rush things,” he said at a White House briefing. “They want to do it after Nov. 3.” That is Election Day.

The FDA did not respond to a request for comment on the president’s Saturday tweets.

A senior administration official, who spoke on the condition of anonymity because he wasn’t authorized to speak publicly about the issue, said the president believes officials at the National Institutes of Health are dragging their feet on the plasma treatment even though many physicians believe it is effective. “Paralysis by analysis,” the official said, explaining why Trump was upset.

The FDA said in a statement this past week that NIH was not involved in the decision-making process at the FDA and that the agency would rule on convalescent plasma “at the appropriate time.”

Trump’s tweets drew swift criticism from scientists and former FDA officials, some of whom have warned for months that he might try to pressure regulators into clearing a coronavirus vaccine before the election, even if it has not been adequately vetted for safety and effectiveness.

“All I can say is that for vaccines, what the President wrote on Twitter this morning is not true,” Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, said in an email. Hotez said the FDA and NIH have been “working day and night to accelerate Operation Warp Speed vaccine clinical trials, but expediting things in a way so as not to compromise the safety of the human volunteers.”

Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, said “he is creating a villain: FDA.”

Offit, who is part of a group helping advise companies and the federal government on vaccine development, said the FDA is requiring companies to go through carefully designed phases of testing, including large Phase 3 trials designed to test effectiveness and safety, to minimize the risk that a product given to healthy people causes harm.

Peggy Hamburg, an FDA commissioner during the Obama administration, said she was “saddened to see that the president clearly does not understand how FDA does its important work or appreciate the value of this unique agency and the contribution it makes to protect the health of Americans.”

“This is no time to politicize the work of FDA,” she added. “It has to have the independence to do its job without fear of retaliation.”

Representatives of the drug industry said the agency is not delaying vaccines for political reasons.

“Everyone is eager to deliver the treatments we need to eradicate this pandemic as quickly as possible, but we can only move as fast as the science allows us,” Rich Masters, Biotechnology Innovation Organization’s executive vice president for public affairs, said in a statement. “We are confident everyone is moving as fast as possible to ensure any vaccine or new therapy is both safe and effective for patients to use.”

Trump and his top advisers have also clashed with top officials from the Centers for Disease Control and Prevention.

The president’s political advisers know that having a vaccine ready — or nearly ready — by Election Day is key to his prospects for winning. And Trump has agitated in a number of meetings for the scientists to be as fast as possible, officials say.

The effort to develop a vaccine has occurred at unprecedented speed. Pharmaceutical giant Pfizer said this past week it has given the vaccine or a placebo to 11,000 of the 30,000 participants needed for its late-stage trial, and biotechnology company Moderna said it has enrolled more than 13,000 people for its trial. The FDA has input into the design of trials but doesn’t oversee trial enrollment.

This past week, Reuters reported that Peter Marks, the FDA career official who heads the agency center that is reviewing vaccines, said he would resign if he were put under political pressure to prematurely approve an inoculation.

In recent months, the FDA has been pressured to review oleandrin, an unproven medical herb, after Trump met in the Oval Office with a company executive pushing the botanical as a covid-19 treatment. The meeting was set up by Mike Lindell, chief executive of My Pillow, and Ben Carson, secretary of housing and urban development.

Administration officials said Trump was briefed on the vaccine effort this past week. Aides are trying to keep him out of the vaccine process because they want it to be viewed as credible and not political, said officials who spoke on the condition of anonymity because they were not authorized to speak on the issue. They said they are devising a communications strategy, to be executed by the White House and the health agencies, to assure the public that any vaccine will be safe and delivered as quickly as possible, but that the president follows his own communications strategy.

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