Dr Anthony Fauci, a top infectious diseases expert in the United States, has said that rushing to distribute coronavirus vaccines under special emergency use guidelines before it has been proven safe in large trials had risks and was a bad idea, Reuters reported on Tuesday.

In an exclusive interview with the news agency, Fauci said, “The one thing that you would not want to see with a vaccine is getting an EUA [emergency use authorisation] before you have a signal of efficacy.” He also said that the rush to have a vaccine could affect the testing of other vaccines.

The Trump administration was considering fast-tracking an experimental United Kingdom vaccine, bypassing standard laws, ahead of the United States presidential election set for November 3, The Financial Times reported.

One of the ways to do this would involve the US Food and Drug Administration granting emergency use authorisation to a vaccine being jointly developed by the Oxford University and pharmaceutical company AstraZeneca, the newspaper reported, citing three unidentified officials who were briefed about the plan.

On Saturday, Trump in a tweet had claimed that the Food and Drug Administration was delaying the vaccine till presidential elections are held. “The deep state, or whoever, over at the FDA [Food and Drug Administration] is making it very difficult for drug companies to get people in order to test the vaccines and therapeutics,” he said. “Obviously, they are hoping to delay the answer until after November 3rd. Must focus on speed, and saving lives!”

Experts and scientists are worried that the Trump administration may force the Food and Drug Administration to develop and distribute a Covid-19 vaccine before it is tested properly.

“I would be very worried about using an EUA [emergency use authorisation] mechanism for something like a vaccine,” said Dr Peter Hotez, an infectious disease expert and vaccine researcher at Baylor College of Medicine. “It’s very different from plasma therapy.”

Emergency use authorisation is for products to “diagnose, prevent and treat serious or life-threatening diseases where the known benefits outweigh the potential risks of the product,” Fauci said, adding that the authority is appropriate when the vaccine has been proven safe and effective.

“To me, it’s absolutely paramount that you definitively show that a vaccine is safe and effective, both,” Fauci said. “We would hope that nothing interferes with the full demonstration that a vaccine is safe and effective.”

Earlier, scientists and experts had raised questions on Russia’s Covid-19 vaccine, which was released before the third phase of clinical trials were conducted. The phase takes several months to complete and also requires the participation of thousands of people.

Globally, the coronavirus has affected more than 2.35 crore people. So far, 8.11 lakh people have died of the infection across the world, while 1.52 crore people have recovered, according to the Johns Hopkins University’s tracker.