A Monash University study showing that a head lice drug kills the COVID-19 virus has prompted warnings from other researchers the level of drug needed was up to 100 times higher than approved human doses.

The publication of the study led to a surge in demand for ivermectin around the world, forcing the US Food and Drug Administration to issue an extraordinary warning urging people not to take the drug, cautioning it “can cause serious harm in people.”

A microscope image of the virus that causes COVID-19. Credit:AP

The study, published on April 3, shows certain concentrations of ivermectin can kill the virus that causes COVID-19 in cells in a test tube.

Ivermectin is a commonly used and inexpensive treatment for parasites, including head lice. It can be taken as a tablet or applied as a cream, and is used as a heartworm medicine for dogs.