A malaria drug taken by U.S. President Donald Trump to prevent Covid-19 did not show any benefit versus placebo in reducing coronavirus infection among healthcare workers, according to clinical trial results published on Wednesday.
The study largely confirms results from a clinical trial in June that showed hydroxychloroquine was ineffective in preventing infection among people exposed to the new coronavirus.
Trump began backing hydroxychloroquine early in the pandemic and told reporters in May he started taking the drug after two White House staffers tested positive for Covid-19. Studies have found the drug to offer little benefit as a treatment.
All eight were either asymptomatic or had mild symptoms that did not require hospitalisation, according to the results published in the JAMA Internal Medicine journal.
The research shows that routine use of the drug cannot be recommended among healthcare workers to prevent Covid-19, researchers from the University of Pennsylvania said.
In the latest trial, which was terminated before it could reach its enrollment target of 200 participants, mild side effects such as diarrhoea were more common in participants taking the malaria drug compared to placebo.