So far though, all the major clinical trials that have reported their findings on this question have found no benefit, and leading national health authorities have moved to restrict its use because of potential cardiac harm.

Nonetheless the family doctor said all 350 patients she had treated with the medicine – including those with serious pre-existing conditions – had survived, and that hydroxychloroquine was so potent it made mask-wearing and lockdowns unnecessary.

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The clip was shared by Trump and described as a “must watch” by his son Donald Trump Jnr, but has since been deleted by Facebook, Twitter and YouTube for promoting misinformation.

Asked later by a reporter about his retweet, the president said: “I thought her voice was an important voice, but I know nothing about her”.

Trump also complained about his plummeting approval ratings as compared to those of Dr Anthony Fauci, the top medical adviser on the White House coronavirus task force.

“He’s got a high approval rating. Why don’t I have a high approval rating?” Trump said. “Nobody likes me … It can only be my personality.”

The debate over hydroxychloroquine has become supercharged politically with leaders like Trump and some fellow US conservatives cheerleading heavily in its favour.

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And the curious case of Immanuel and colleagues – first reported in depth by The Daily Beast – underscores just how far the drug’s advocates are willing to go.

The website for “America’s Frontline Doctors” was registered just 11 days ago, a web domain age checker revealed – and the site was taken down by Tuesday afternoon.

“Tea Party Patriots”, a right-wing political group backed by wealthy Republicans, said on its website it was responsible for organising the Washington summit.

Further research on Immanuel’s web page, now accessible only via an archived website viewer, as well as her YouTube account, reveal a long list of bizarre and unscientific beliefs.

These include that “tormenting spirits” routinely have “astral sex” with women, which in turn causes “gynaecological problems, marital distress, miscarriages” and more.

In a 2015 video, Immanuel, who leads a religious group called Fire Power Ministries, said: “There are people ruling this nation that are not even human,” describing them as “reptilian spirits” who are “half human, half ET.”

In the same video she rails against the use of “alien DNA” to treat sick people, which she said had resulted in human beings mixing with demons.

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Other targets of her anger include gay marriage, which she said would result in adults marrying children.

Immanuel was born in 1965, received her medical degree at the University of Calabar in Nigeria, and has a valid physician’s license, according to the website of the Texas Medical Board.

After Facebook took down the clip, Immanuel warned that the company’s servers would start crashing until it was restored.

“If my page is not back up face book will be down in Jesus name,” she tweeted.

Additional reporting by Tribune News Service