WASHINGTON, July 10 — US President Donald Trump continues to see a malaria drug, hydroxychloroquine, as a promising drug to be used to prevent infection with the coronavirus, the White House said yesterday, though the US Food and Drug Administration has said its efficacy and safety were unproven.

"The president has always said that he sees hydroxychloroquine as a very promising prophylactic but that every person should not take it unless they get a prescription from their doctor,” White House spokeswoman Kayleigh McEnany said at a news conference.

Trump told reporters in May he had started taking hydroxychloroquine after two White House staffers tested positive for Covid-19. His doctor said last month that Trump had suffered from no side effects after a two-week course of the malaria drug, which can cause heart problems.

Earlier this week, another world leader, Brazilian President Jair Bolsonaro, said he had tested positive for the virus and was taking hydroxychloroquine. Bolsonaro has pushed his government to make the drug widely available and has encouraged Brazilians to take it both to treat Covid-19 and to prevent it. — Reuters