While researchers try to find a vaccine, the coronavirus epidemic brought a surge in demand for drugs normally used against malaria to tackle the coronavirus with Chloroquine, and a related derivative, Hydroxychloroquine, gaining attention.

Nevertheless, the evidence doesn’t actually support the use of neither of those drugs to prevent COVID-19 or for the treatment of patients with COVID-19, according to a new study.

Researchers from the American College of Physicians (ACP) said that both drugs should only be used to treat hospitalized COVID-19 positive patients in the context of a clinical trial following shared and informed decision-making between clinicians and patients.

Chloroquine and hydroxychloroquine are used to manage other major illnesses with a known benefit and are now in short supply in the United States. They have known (and harmful) side-effects in non-COVID patients such as cardiovascular effects; diarrhea; abnormal liver function; rash; headache; ocular issues; and anemia.

“Current evidence about efficacy and harms for use in the context of COVID-19 is sparse, conflicting, and from low quality studies, increasing the uncertainty and lowering our confidence in the conclusions of these studies when assessing the benefits or understanding the balance when compared with harms,” the authors wrote regarding the drugs.

US President Trump has frequently referred to the potential of hydroxychloroquine in White House briefings. At one press conference, he said: “What do you have to lose? Take it.” Meanwhile, Brazilian President Jair Bolsonaro claimed in a video that “hydroxychloroquine is working in all places.”

More than 20 trials aiming to test the effectiveness of the drugs on COVID-19 patients are being carried out in the US, UK, Spain, and China, among other countries. In the US, trials are also looking into a combination of drugs including chloroquine, hydroxychloroquine, and an antibiotic called azithromycin for the treatment of Covid-19.

In late March, the US Food and Drugs Administration (FDA) granted “emergency use” authorization for these drugs in the treatment of Covid-19 for a limited number of hospitalized cases. That does not mean the FDA is saying they definitely work. But it does mean that in specific circumstances, hospitals can use the drugs on Covid-19 patients.

The US government has said that 30 million doses of hydroxychloroquine have been donated to the national stockpile by a German-based pharmaceutical company. Other countries are also deploying these anti-malarial drugs to varying degrees. France, for example, has also authorized doctors to prescribe them for patients with Covid-19.

India’s health ministry has recommended the use of hydroxychloroquine as a preventative treatment for healthcare workers, as well as for households in contact with confirmed cases if they have a prescription from a doctor. However, India’s government research body has warned against their unrestricted usage.

The study was published in Annals of Internal Medicine.