Hydroxychloroquine, a decades-old malaria drug touted by President Donald Trump, didn't appear to help hospitalized patients with Covid-19, according to a new observational study published Thursday in the New England Journal of Medicine.

The study, funded by the National Institutes of Health and conducted by researchers at New York-Presbyterian Hospital and Columbia University Irving Medical Center in New York City, looked at 1,376 consecutive patients who showed up at the emergency room with symptoms of coronavirus.

Nearly 60%, or 811 of the patients, received the drug within 48 hours and were found, on average, to be more severely ill than those who didn't receive the drug, the researchers said.