Canadian health authorities have issued a warning against the use of anti-malarial drugs chloroquine and hydroxychloroquine to treat coronavirus infections or prevent reinfections, according to AFP.

“Chloroquine and hydroxychloroquine can have serious side effects. These drugs should be used only under the supervision of a physician,” Canada's public health agency said in a note posted on its website.

“Health Canada is concerned that some people may be directly buying and using chloroquine or hydroxychloroquine to prevent or treat Covid-19,” it said, noting they can cause “serious heart rhythm problems".