The antiviral drug Remdesivir, considered one of the most promising treatments against Covid-19, turns out to be ineffective in preventing death from this disease, according to a study supported by the World Health Organization (WHO).

The drug "seems to have little or no effect on those hospitalized by Covid-19, as indicated by the rates of mortality, the start of respiratory assistance or the length of hospital stay," explains this study published online Thursday night.

Remdesivir, which was part of the experimental cocktail administered to US President Donald Trump after contracting the coronavirus last month, is one of several drugs reviewed by this large study of more than 11,000 people in 30 countries.

The data, which has not yet been reviewed by other doctors before being published in a scientific journal, appear to contradict at least two large American studies that showed that Remdesivir could reduce the length of hospitalizations of patients with Covid-19.