Hydroxychloroquine ineffective in preventing COVID-19: study

Hydroxychloroquine is not effective in preventing the development of COVID-19 in people exposed to the novel coronavirus, a new study involving Canadian researchers concludes.

The results were published Wednesday in the New England Journal of Medicine.

The clinical trial was led in Canada by Dr. Todd Lee and Dr. Emily McDonald of the Research Institute of the McGill University Health Centre, in conjunction with partners at the University of Manitoba and University of Alberta.

The Canadian research is coordinated with a large study by Dr. David Boulware at the University of Minnesota.

It is the first double-blind, randomized, placebo-controlled trial to be completed assessing the effectiveness of the malaria drug hydroxychloroquine in preventing COVID-19.

“We conducted an international, randomized controlled trial to look at whether the use of hydroxychloroquine in patients who’d had a high-risk exposure to COVID-19 would prevent the development of symptomatic disease compared to placebo,” Lee said in an interview.

Participants were recruited from Quebec, Manitoba, Alberta and across the United States. In total, the study involved 821 asymptomatic adults who had been exposed at home or in the health-care setting to someone with COVID-19.

Among them, 719 participants reported a high-risk exposure to a confirmed case of COVID-19 — being within two metres of the person for more than 10 minutes — without adequate personal protective equipment.

Most of these people were healthy young adults living in the community, with an average age of 40.

Within four days of exposure, participants received the placebo or hydroxychloroquine by mail, to be taken for a period of five days, beginning with a higher dose on the first day. Researchers and participants were not told which treatment was being administered.