Hydroxychloroquine has been making headlines recently, as a drug that may help prevent development of the Covid-19 virus in those who have been infected. It also made headlines when US President Trump suggested people should take it because he ‘heard it could stop it’ – despite warnings from scientists and medical experts saying more studies needed to be done. They even warned of the possibility of it causing serious or deadly side effects. More recently, Trump announced that he decided to take the drug as a preventative measure against Covid-19. Whether or not he really took it is questionable, given the President’s propensity to claim things having no basis in fact.
According to a June 3rd press release, a clinical trial done by the Research Institute of the McGill University Health Centre (in collaboration with the Universities of Manitoba and Alberta), concluded hydroxychloroquine is not effective in preventing the development of the SARS-CoV-2 virus. It was the first double-blind, randomized, placebo-controlled trial of using the drug for disease prevention to be completed. Here are some details (the full document can be found in the New England Journal of Medicine):
Hydroxychloroquine not effective against COVID-19 when used as post-exposure prophylaxis (prevention measure taken).
A new study suggests that hydroxychloroquine is not effective in preventing the development of COVID-19 in individuals exposed to SARS-CoV-2, the virus responsible for the disease. This is the main conclusion of the first double-blind, randomized, placebo-controlled trial of hydroxychloroquine for disease prevention to be completed. Coordinated with a large study led by Dr. David Boulware at the University of Minnesota, this clinical trial was led in Canada by Drs. Todd Lee and Emily G. McDonald at the Research Institute of the McGill University Health Centre (RI-MUHC), in collaboration with partners at the Universities of Manitoba and Alberta.
“While we had hope this drug would work in this context, our study demonstrates that hydroxychloroquine is no better than placebo when used as post-exposure prophylaxis within 4 days of exposure to someone infected with the new coronavirus,” says Dr. Lee, Scientist at the RI-MUHC and Associate Professor of Medicine, Division of Infectious Diseases at McGill University and one of the lead authors of the study.
This trial included 821 asymptomatic adults with household or healthcare exposure to someone with confirmed COVID-19, who were enrolled nationwide in the United States and in the Canadian provinces of Quebec, Manitoba, and Alberta. Among them, 719 participants reported a high-risk exposure, of less than six feet (2 metres) for more than 10 minutes without one of the components of personal protective equipment (e.g. mask or face shield), to a confirmed COVID-19contact. For the most part, they were healthy younger community dwelling adults (average age 40 years).
Within four days of exposure, the participants received either placebo or hydroxychloroquine by commercial courier, which were to be taken over five days, starting with a stronger dose on day 1. Investigators and participants were blinded to the treatment assignments, and an independent data and safety monitoring board (DSMB) externally reviewed the data.
“This is the gold standard method for this type of intervention,” says Dr. McDonald, Investigator at the RI-MUHC, Director of the MUHC Clinical Practice Assessment Unit and co-author of the study. “It is incredibly important that we complete randomized controlled trials so that we have the best available evidence for how to prevent the spread of COVID-19.”
Overall, 107 of 821 of participants developed COVID-19 (either confirmed with a test or symptomatically compatible disease) over the 14 days of follow-up. Both confirmed cases and probable cases were included, due to some lack of availability of diagnostic testing in the United States. Amongst those who received hydroxychloroquine, 49 developed the disease (or compatible symptoms such as fever or cough), vs 58 in the group that received the placebo. Two patients were hospitalized, one in each group. No deaths occurred.
Medication side effects like nausea and abdominal discomfort were more common for patients taking hydroxychloroquine compared to placebo (40% vs. 17%), but no serious treatment-related adverse reactions were reported, including any heart arrhythmia.
‘’Our study’s results set politics aside and provide unbiased evidence to guide practice in the prevention of COVID-19 and reinforce the importance of randomized clinical trials as we work together nationally and internationally to combat the novel coronavirus,’’ 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. More research is needed to determine whether hydroxychloroquine can be effective for the early treatment of COVID-19, and whether pre-exposure prophylaxis could be effective in high-risk populations. Various trials are ongoing worldwide, including in Canada (covid-19research.ca). At the MUHC, a trial looking at early treatment in the community is underway.