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Antimalarial drug does not necessarily prevent coronavirus

Credit: Belga

Taking hydroxychloroquine shortly after being exposed to coronavirus does not necessarily prevent infection, researchers reported Wednesday following a clinical trial.

The drug, primarily used against malaria, was praised by United States President Donald Trump, who said he was using it preventively against the new coronavirus (Covid-19). 

A study of 821 people in the United States and Canada showed that it was not much more effective than a placebo for this purpose.

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A team of scientists led by the University of Minnesota selected adults who had been in contact with a coronavirus-positive person for more than 10 minutes at a distance of two metres or less.

The majority of them were considered “at risk” of infection as they were not wearing masks or eye protection when they interacted with the infected person.

All were randomly given either hydroxychloroquine or a placebo within four days of contact. The researchers then analyzed how many of them contracted coronavirus within two weeks.

“This randomised trial did not show a significant benefit of hydroxychloroquine as a prophylactic treatment after exposure to Covid-19,” the authors concluded.

49 of the 414 patients (12%) who received treatment developed the disease, compared to 58 of the 407 (14%) who received placebo. That difference is not considered statistically significant.

Gold standard
The results of the study were eagerly awaited because it was a randomised controlled trial, an experiment that is considered the gold standard for the study of clinical outcomes.

Still, “the study is too small to be conclusive,” warns Martin Landray, a professor of medicine and epidemiology at Oxford University, who was not involved in the design of the study.

More studies will be needed to know for sure whether hydroxychloroquine can have a moderate positive effect, the expert believes.

Flawed data
On Wednesday, the World Health Organization (WHO) announced the upcoming resumption of clinical trials of hydroxychloroquine against coronavirus. 

The week before, it had announced it would no longer administer hydroxychloroquine in its tests because of “concerns about the safety of the trials” after a study to that effect in the Lancet. 

However, on Tuesday the journal distanced itself from its own study. It acknowledged in a formal warning that “important questions” remained.

“Data for multiple studies on Covid-19” was provided by “a little-known US healthcare analytics company,” according to the Guardian. The newspaper said the research was based on “flawed data.”

Jason Spinks
The Brussels Times