Like his US counterpart Donald Trump, Brazilian President Jair Bolsonaro has touted the supposed benefits of hydroxychloroquine and a related drug, chloroquine, against the new coronavirus.

Studies, however, have questioned their safety and efficacy against the disease, including one published Friday in respected medical journal The Lancet that found the drugs actually increased the risk of death.

The guideline recommended doctors in the public health system prescribe either chloroquine or hydroxychloroquine from the onset of Covid-19 symptoms.

Preliminary studies in China and France had generated hope the drugs might be effective against the new coronavirus.

"It wasn't a clinical trial, it was just a data set collected from different countries, and that doesn't meet the criteria of a methodologically acceptable study to serve as a reference for any country in the world, including Brazil," she said.