The European Commission says there is no evidence that a drug touted by US president Donald Trump as a potential miracle cure for Covid-19 was effective against the disease caused by the new coronavirus.

Mr Trump had said that hydroxychloroquine, an anti-malaria drug, could be among “the biggest game changers in the history of medicine” for its potential effects against Covid-19.

He has been particularly enthusiastic about the potential use of the drug, despite Dr Anthony Fauci, his lead coronavirus expert, warning that any evidence was “anecdotal”.

A spokesperson for the European Commission, relaying an internal opinion from the European Medicine Agency, said: “The efficacy of hydroxychloroquine in the treatment of Covid-19 patients has to date not been proved.”

The spokesperson went on to say that there was also no evidence of any positive effects from chloroquine, another malaria drug, which is also being tested for its possible use against Covid-19.

In China, a report published by the Journal of Zhejiang University tested if coronavirus patients who received hydroxychloroquine were more likely to recover than those who didn’t, and it found that was not the case.

This limited study only looked at 30 patients and contrasted a study in France, which looked at 40 patients. In France, its study found the virus decreased in patients when used with the combination of an antibiotic.

In the US on 23 March, the Food and Drug Administration (FDA) approved a similar study in New York to that conducted in France, combining malaria drugs with antibiotics. The agency sent 750,000 doses of chloroquine, 75,000 doses of hydroxychloroquine and 10,000 doses of Zithromax (the antibiotic azithromycin) to assist the state with its drug trials.

Unfortunately, widely broadcasting enthusiasm for, and anecdotal evidence of, the efficacy of chloroquine led to the death of an Arizona man after he self-medicated with an additive used to clean fish tanks, that included chloroquine phosphate.

His wife also took the mixture and ended up in the ICU battling the effects of the solution. She told NBC News that they had been afraid of getting sick from the virus and decided to try the mixture after hearing about it during one of the president’s press conferences.

States including Nevada, Illinois, Ohio, North Carolina, and Texas have noticed doctors hoarding the drugs and released recommendations to deter any abuse by prescribers.

On 26 March, the US Department of Health and Human Services listed hydroxychloroquine as a protected medical resource after Trump signed an executive order to prevent its hoarding and price gouging.

Last week in Europe, Hungary, a European Union member, also banned the commercial export of hydroxychloroquine.

“As Hungary is one of the world's largest exporters of this ingredient, the protection and medical supply of the Hungarian population is now a priority,” the Hungarian government said.

With reporting from ​Reuters