The first high-quality hydroxychloroquine trial found that it does not prevent coronavirus infections, according to a study published in the New England Journal of Medicine.
Days after President Donald Trump said he took a 14-day course of hydroxychloroquine, an anti-malarial drug that is also prescribed for lupus and rheumatoid arthritis, as a prophylactic to prevent coronavirus infection, researchers said there is no evidence the drug works that way.
Researchers gave the drug or a placebo to more than 800 volunteers but found that the drug did no better than the placebo at preventing infection.
The drug did not seem to cause serious side effects but about 40% reported mild side effects, mostly stomach problems.
"We were disappointed. We would have liked for this to work," lead researcher Dr. David Boulware, an infectious disease specialist at the University of Minnesota, told CBS News. "But our objective was to answer the question and to conduct a high-quality study.”
After 14 days in the study, 12% of people who took the drug developed coronavirus symptoms compared to 14% of the placebo group.
"There's basically no effect. It does not prevent infection," Boulware said. "We'd want a much larger effect" to justify its use.
Results were no different among subgroups given zinc or vitamin C with the hydroxychloroquine.
Studies continue to disprove hydroxychloroquine effect:
Despite Trump’s recommendations, studies have found that the drug has no benefit in treating the coronavirus.
"This fits with everything else we've seen so far which suggests that it's not beneficial," Dr. Peter Bach, director of a health policy center at Memorial Sloan Kettering Cancer Center in New York, told CBS.
The latest study included many younger people which "would make me very discouraged about trying to use this in older people" he added. "If it does work, it doesn't work very well."
"This trial is fairly conclusive that there is not a benefit for post-exposure prophylaxis," Boulware told Business Insider. "If you're the general public, if you're the president or anyone, and you're exposed to somebody with known COVID, taking this is not going to reduce your risk of developing infection."