Last week, World Health Organization announced that it had temporarily paused the hydroxychloroquine arms of the trial due to concerns surrounding the drug's safety. Trump, too, said he took hydroxychloroquine to prevent infection.
The key finding is that hydroxychloroquine, the most common preparation of drugs typically used to prevent malaria and to help those with autoimmune conditions such as lupus and rheumatoid arthritis, "was not able to prevent the development of COVID-19 any better than a placebo".
"We launched the first COVID-19 clinical trial in Manitoba, and played a key role in promoting this important randomized clinical trial across Canada", said Dr. Ryan Zarychanski, Manitoba lead and associate professor of internal medicine, Max Rady College of Medicine, University of Manitoba and senior scientist, Research Institute in Oncology and Hematology.
Currently, there is no approved treatment for COVID-19.
However, the drug did not seem to cause serious harm, though - about 40% on it had side effects, mostly mild stomach problems.
Some European governments banned hydroxychloroquine for COVID-19 patients, and US hospitals have significantly cut back its use.
Dominic Cummings or the national interest? Legislator Grills Johnson
He has received the continued support of the prime minister, who said that his aide had acted legally and with integrity. This was Mr Johnson's first appearance before the committee since he became PM last July.
Surgisphere Corporation, an IL based company which owns the dataset behind the study published in The Lancet as well as a study in the New England Journal of Medicine, has been subject to scrutiny in recent days as clinicians and researchers challenge the likelihood of assembling the amount of data supplied by the firm in such a short period of time.
It followed numerous smaller studies that suggested hydroxychloroquine is ineffective in treating COVID-19.
WHO officials said they were especially anxious about outbreaks in Latin America and Haiti, one of the world's poorest nations, where infections have been spreading rapidly. "Universal face mask use might enable safe lifting of restrictions in communities seeking to resume normal activities and could protect people in crowded public settings and within households", Raina MacIntyre, professor of global biosecurity at the University of New South Wales in Sydney, said in a linked comment on the study.
The study, coordinated with a larger study led by the University of Minnesota, included researchers from the U of M, University of Alberta and McGill University.
In March, Trump said hydroxychloroquine used in combination with the antibiotic azithromycin had "a real chance to be one of the biggest game changers in the history of medicine" with little evidence to back up that claim. The trial was double-blinded, meaning that neither the subjects nor the researchers knew which treatment they were receiving. He said he would favor doing another study with viral testing.