The drug has been used to treat a number of diseases in the past half-century but after a French study claimed it was effective against coronavirus it has been hailed by the US president as a cure. But there is scant evidence it is effective – and it could actually be harmful

At one of his recent daily press briefings, Donald Trump told his global television audience he was hearing great things about the malaria drug hydroxychloroquine for treating coronavirus. “I think it could be, based on what I see, it could be a game changer,” he said.

But despite big claims for the drug in a small study in France, the evidence for hydroxychloroquine as a treatment for Covid-19 is scant – and certainly far from reliable enough to put into widespread use. So how did Trump come to recommend it to the extent that he declared: “What do you have to lose?”

The Guardian’s Julia Carrie Wong tells Rachel Humphreys that before reaching Trump, the hype around hydroxychloroquine, which is also used to treat rheumatoid arthritis and lupus, had moved from small clinical studies through to influencers in Silicon Valley and then on to prime time shows on Fox News. But rather than being 100% effective as has been claimed, there are serious doubts about the drugs safety when taken to treat coronavirus.