The World Health Organisation (WHO) suspended trials of the drug that US president Donald Trump has promoted as a coronavirus defence, fuelling concerns about his handling of the pandemic that has killed nearly 100,000 US citizens.
Trump has led the push for hydroxychloroquine as a potential shield or treatment for the virus, which has infected nearly 5.5 million people and killed 345,000 around the world, saying he took a course of the drug as a preventative measure.
Brazilian President Jair Bolsonaro has also heavily promoted hydroxychloroquine while the virus has exploded across the nation, which this week became the second most infected in the world after the US.
But the WHO on Monday said it was halting testing of the drug for Covid-19 after studies questioned its safety, including one published on Friday in medical journal The Lancet that found it increased the risk of death.
The WHO “has implemented a temporary pause … while the safety data is reviewed”, its chief Tedros Adhanom Ghebreyesus said, referring to the hydroxychloroquine arm of a global trial of various possible treatments.
Last week, Trump announced that he was taking the drug, explaining he had decided to take it after receiving letters from a doctor and other people advocating it.
“I think it’s good. I’ve heard a lot of good stories,” Trump told reporters then, as he declared it safe.
Trump dismissed the opinions then of his own government’s experts who had warned of the serious risks associated with hydroxychloroquine, with the Food and Drug Administration highlighting reported poisonings and heart problems.
Trump has been heavily criticised for his handling of the virus, after initially downplaying the threat and then repeatedly rejecting scientific analysis.
The US has by far the world’s highest coronavirus death toll, reaching 98,223 on Tuesday, with more than 1.66 million confirmed infections, shows a tally by Johns Hopkins University in the US state of Maryland.
Despite the WHO suspension, Brazil’s health ministry on Monday it would keep recommending hydroxychloroquine for Covid-19.
“We’re remaining calm and there will be no change,” ministry official Mayra Pinheiro told a news conference.
“As for the studies that are being talked about, or that particular [The Lancet] study, these are not clinical trials, but merely a collection of samples from several countries.
“This does not fit into a methodologically acceptable study criterion to serve as a reference for any country in the world, much less for Brazil,” she said.
Bolsonaro is a staunch opponent of lockdown measures and like Trump has played down the threat of the virus, even as Latin America has emerged as the new global virus hotspot.
Brazil has reported nearly 375,000 cases, widely considered to be far fewer than the real number because of a lack of testing, and more than 23,000 deaths.
Chile also is in the grip of a virus surge, with a record of nearly 5,000 infections in 24 hours on Monday.
While South America and parts of Africa and Asia are only just beginning to feel the full force of the pandemic, many European nations are easing lockdowns as their outbreaks are brought under control.
In hard-hit Spain, Madrid and Barcelona on Monday emerged from one of the world’s strictest lockdowns, with parks and cafe terraces open for the first time in more than two months.
Elsewhere, gyms and swimming pools reopened in Germany, Iceland, Italy and Spain.
And slowing infection rates in Greece allowed restaurants to resume business a week ahead of schedule – but only for outdoor service.
Despite the encouraging numbers, experts have warned that the virus could hit back with a devastating second wave if governments and citizens are careless, especially in the absence of a vaccine.
The latest reminder of the threat came from Sweden, where the Covid-19 death toll crossed 4,000 – a much higher figure than its neighbours.
The Scandinavian nation has gained international attention – and criticism – for not enforcing stay-at-home measures like other European countries.
In India, domestic flights resumed even as coronavirus cases surge, while confusion about quarantine rules prompted jitters among passengers and the cancellation of dozens of planes.
Thailand is conducting tests on macaque monkeys as it races to produce a cheaper, alternative coronavirus vaccine it hopes will be ready by next year, a top researcher has said.
More than 100 candidate vaccines are currently in various stages of development around the world, at least eight of which are in clinical trials with humans, said the WHO.