Researchers say that a malaria drug President Donald Trump took to try to prevent COVID-19 proved ineffective for that in the first large, high-quality study to test it in health workers and others closely exposed to people with the disease.
Results published Wednesday by the New England Journal of Medicine show that hydroxychloroquine was no better than placebo pills at preventing illness from the coronavirus.
“After high-risk or moderate-risk exposure to COVID-19, hydroxychloroquine did not prevent illness compatible with COVID-19 or confirmed infection when used as postexposure prophylaxis within four days after exposure,” researchers concluded.
The study involved 821 people in the U.S. or Canada who took the drug or placebo pills for five days. Two weeks later, illness rates were similar in both groups.
After 14 days in the study, 12% on the drug developed COVID-19 symptoms versus 14% in the placebo group, but the difference is so small it could have occurred by chance, study leader Dr. David Boulware told The Associated Press.
“There’s basically no effect. It does not prevent infection,” said the infectious disease specialist at the University of Minnesota.
The study notes that side effects were about 23% more common with hydroxychloroquine than with the placebo, but no serious adverse reactions were reported.
“We were disappointed. We would have liked for this to work,” Boulware said.
Boulware added that their objective was to answer if the drug was effective and to conduct a high-quality study, because the evidence on the drug so far has been inconclusive.