Antimalarial drug fails to prevent COVID-19 in rigorous study


An antimalarial drug that President Donald Trump took to try to prevent COVID-19 proved to be ineffective for this 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 for preventing coronavirus disease. However, the drug does not seem to cause serious harm – about 40% of them have side effects, mostly mild stomach problems.

“We were disappointed. We would have liked it to work, “said study leader Dr. David Boulware, an infectious disease specialist at the University of Minnesota. “But our goal was to answer the question and conduct a high-quality study,” because the evidence on the drug has so far been inconclusive, he said.

Hydroxychloroquine and a similar drug, chloroquine, have been the subject of much debate since Trump started promoting them in March. Hydroxychloroquine has long been used for malaria, lupus and rheumatoid arthritis, but no large studies have shown that chloroquine is safe or effective for much sicker patients with coronavirus, and some studies have suggested that the drugs could harm.

Trump took a two-week course of hydroxychloroquine, as well as zinc and vitamin D, after two staff members tested positive for COVID-19, and had no adverse effects, according to the results of his last physical examination published by his doctor on Wednesday.

Federal regulators have warned against their use except in hospitals and formal studies because of the risk of side effects, especially heart rhythm problems.

The Boulware study looked at 821 people in the United States and Canada living with someone diagnosed with COVID-19 or at high risk of getting it because of their work – doctors, nurses, paramedics who were exposed to significantly to a sick patient without wearing full protective equipment.

They were randomly assigned to receive either placebo tablets or hydroxychloroquine for five days, starting within four days of exposure. Neither they nor their doctors knew who was receiving what.

After 14 days in the study, 12% of the drug developed COVID-19 symptoms compared to 14% in the placebo group, but the difference is so small that it could have happened by chance, said Boulware.

“There is practically no effect. It doesn’t stop the infection, “he said of the drug. Even if it were to give a slight advantage, “we would like a much greater effect” to justify its use and the risk of side effects to prevent the disease, he said.

The results were no different in a subgroup of participants taking zinc or vitamin C, which some people say may help make hydroxychloroquine more effective.

“This fits with everything we’ve seen so far, suggesting that it’s not beneficial,” said Dr. Peter Bach, director of health policy. center at the Memorial Sloan Kettering Cancer Center in New York.

The study looked at younger, healthy people, but the results “would strongly discourage me from trying to use it in the elderly,” who are most vulnerable to serious coronavirus disease, said Bach. “If it works, it doesn’t work very well. “

Dr. Dan Culver, a lung specialist at the Cleveland Clinic, said it was always possible that administering the drug sooner than four days after someone had been exposed to the virus could help prevent the disease.

But the study “clears the home run from the table” when it comes to hopes for the drug, he said.

The study was primarily funded by David Baszucki, founder of Roblox, a California-based gaming software company, and other private donors and the University of Minnesota.

Boulware is also leading a study testing hydroxychloroquine for the treatment of COVID-19. The study is complete and the results are being analyzed.

The Lancet newspaper on Tuesday published an “expression of concern” about a study released earlier this month on nearly 15,000 COVID-19 patients on malaria drugs that linked their use to a higher risk high to die in hospital or develop a heart problem. .

Scientists have raised serious questions about the database used for this study and its authors have launched an independent audit.

This work had a great impact: the World Health Organization has suspended the use of hydroxychloroquine in a study it is conducting, and the French authorities have stopped the use of the drug in hospitals. The WHO said on Wednesday that the experts who examined the security information decided that its study could be resumed.


Marilynn Marchione can be followed on Twitter: @MMarchioneAP


The Associated Press’s Department of Health and Science is supported by the Department of Science Education at the Howard Hughes Medical Institute. The AP is solely responsible for all content.

Marilynn Marchione, The Associated Press


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