Facing potential malaria drug shortages, the European Medicine Agency (EMA) urged countries on Wednesday to use the medicines sparingly to treat COVID-19.

The anti-malarial drugs hydroxychloroquine and chloroquine should only be sued in clinical trials or in "national emergency programs," the EMA said in a statement.

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With a COVID-19 vaccine likely still months away, the drugs are being tested in several countries for their ability to treat the deadly and highly-contagious virus.

Despite early success in trials in China and France, the EMA emphasized that their "efficacy in treating COVID-19 is yet to be shown in studies."

It will likely be over a year until a coronavirus vaccine is developed

Drugs running low in US

The drugs are also key treatments for patients with autoimmune disorders such as lupus, who could face critical shortages due to drug hoarding.

"It is important that such patients are still able to obtain them and do not face shortages caused by stockpiling or use outside the authorized indications," the EMA said in a statement.

The United States has already logged shortages of both drugs, particularly after President Donald Trump touted hydroxychloroquine as a potential "game changer."

EU and US health officials have cautioned people against taking anti-malarial drugs to treat COVID-19 infections without a prescription and supervision by a doctor.

"Both chloroquine and hydroxychloroquine can have serious side effects, especially at high doses or when combined with other medicines," the EMA warned.

Side effects include heart problems, vision loss or even death if used incorrectly.

Watch video 03:31 Coronavirus medications and vaccines – Q & A with DW's science correspondent Derrick Williams

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rs/sms (AFP, Reuters)