The World Health Organization has temporarily halted studying hydroxychloroquine as a potential Covid-19 treatment due to safety concerns, WHO Director-General Tedros Adhanom Ghebreyesus said during a media briefing in Geneva on Monday. The decision was made after an observational study published Friday in the medical journal The Lancet described how seriously ill Covid-19 patients who were treated with hydroxychloroquine and chloroquine were more likely to die. Tedros said that an independent executive group is now reviewing the use of hydroxychloroquine in WHO’s Solidarity Trial. The executive group represents 10 of the participating countries in the trial. “The review will consider data collected so far in the Solidarity Trial and, in particular robust randomized available data, to adequately evaluate the potential benefits and harms from this drug,” Tedros said. “The Executive Group has implemented a temporary pause of the hydroxychloroquine arm within the Solidarity Trial while the data is reviewed by the Data Safety Monitoring Board.” The trial, which involves actively recruiting patients from more than 400 hospitals in 35 countries, is a global research effort to find safe and effective therapeutics for Covid-19. Tedros added that the other arms of the trial are continuing. “This concern relates to the use of hydroxychloroquine and chloroquine in Covid-19,” he said. “I wish to reiterate that these drugs are accepted as generally safe for use in patients with autoimmune diseases or malaria.” Dr. Soumya Swaminathan, WHO chief scientist, said Monday the trial has only been using hydroxychloroquine, not the more toxic chloroquine. President claims he took the drug President Donald Trump claimed on May 18 that he was taking daily doses of hydroxychloroquine. Trump said he has taken the antimalarial drug after consulting the White House doctor, though stopped short of saying his physician had actually recommended the drug. “A couple of weeks ago, I started taking it,” Trump said. He later said he’d been taking it every day for a week and a half. Trump said he hadn’t been exposed to coronavirus, and he started taking the drug because he had heard from frontline responders who sent him letters saying they were taking it preventatively. “Here’s my evidence: I get a lot of positive calls about it,” Trump said. Asked if the White House doctor recommended he begin taking hydroxychloroquine, Trump told reporters he “asked him what do you think, he said, ‘Well if you’d like it.’” Navy Cmdr. Sean Conley, the President’s physician, said Trump had taken multiple tests for coronavirus, which all came out negative. The President remains symptom free, Conley said. “After numerous discussions, he and I had regarding the evidence for and against the use of hydroxychloroquine, we concluded the potential benefit from treatment outweighed the relative risks,” Conley said. Trump’s comments about hydroxychloroquine have led to the soaring sales of the drug.