Anti-malarial drug hydroxychloroquine failed to prevent healthy people, who were exposed to the novel coronavirus, from getting the infection, according to a study published in the New England Journal of Medicine on Wednesday. It was the first major randomised clinical trial looking at whether the medication might be useful as a prophylactic.
The findings came on the same day the World Health Organization said that it will resume clinical trials of the drug. Last week, the global body had decided to temporarily halt its use citing safety concerns.
The study was conducted by the University of Minnesota Medical School. The researchers enrolled over 800 adults in the United States and Canada who were exposed to someone with Covid-19. While some of the participants were asked to take pills of hydroxychloroquine for five days, others were given a placebo – in this case, a vitamin, reported The Washington Post. At the end of a two-week period, about 12% of those given hydroxychloroquine reported symptoms. It was no better than the placebo – nearly 14% of the participants who were asked to take the vitamin pill reported symptoms.
“Our objective was to answer the question of whether hydroxychloroquine worked to prevent disease or did not work,” Dr David Boulware, the lead researcher and an infectious diseases physician at the University of Minnesota, said in a statement. He added the team was “disappointed that this did not prevent Covid-19”.
However, 40% of the participants who took the drug developed side effects like nausea, upset stomach and diarrhoea. But the researchers did not find that the drug led to serious heart problems – a concern that had earlier forced WHO to suspend the clinical trials of the drug. The decision to ban the anti-malarial drug was taken based on a study in medical journal The Lancet, published on May 22. The study had said that hydroxychloroquine could increase patient mortality rate in hospitals. The study also found that those administered the drug showed a higher frequency of arrhythmia, or irregular heartbeat.
Use of hydroxychloroquine to prevent and treat Covid-19 has been a focus of public attention. India has been using the drug extensively and has also exported it to many foreign countries, including the United States. On May 22, the Ministry of Health and Family Welfare revised its advisory on the use of hydroxychloroquine as a prophylactic against the coronavirus. The ministry’s decision came after the National Task Force, constituted by the Indian Council of Medical Research, reviewed and recommended the use of the drug for coronavirus patients.
United States President Donald Trump has also promoted the drug despite the absence of evidence to prove its effectiveness and last month said he was taking it himself in hopes of preventing the infection. In April, he lauded Indian Prime Minister Narendra Modi’s decision to supply the drug to the United States.
As of now, there’s no evidence that any drug effectively works to reduce the mortality among Covid-19 patients, WHO officials said on Wednesday.
“This study doesn’t tell me for sure that this strategy doesn’t work,” said Dr Daniel Culver, a pulmonary and critical care expert at the Cleveland Clinic who was not involved with the research. “It just makes me lean in that direction.” However, Culver said he would continue to encourage people to conduct more clinical trials.