Hydroxychloroquine, the drug backed by President Donald Trump to combat COVID-19, is no better than a placebo in preventing infection of the coronavirus, according to results published Wednesday in the New England Journal of Medicine.

The study, the first randomized, placebo-controlled trial, which is considered the "gold standard" in science, looked at 821 people in the United States and Canada who had been exposed to the coronavirus.

The researchers, led by Dr. David Boulware, an infectious disease researcher at the University of Minnesota, said the drug was given to 414 people for ...