A cheap antidepressant reduced the need for hospitalization among high-risk adults with COVID-19 in a study hunting for existing drugs that could be repurposed to treat coronavirus.

Researchers tested the pill used for depression and obsessive-compulsive disorder because it was known to reduce inflammation and looked promising in smaller studies.

They’ve shared the results with the U.S. National Institutes of Health, which publishes treatment guidelines, and they hope for a World Health Organization recommendation.

“If WHO recommends this, you will see it widely taken up,” said study co-author Dr. Edward Mills of McMaster University in Hamilton, Ontario, adding that many poor nations have the drug readily available. “We hope it will lead to a lot of lives saved.”

The pill, called fluvoxamine, would cost $4 for a course of COVID-19 treatment. By comparison, antibody IV treatments cost about $2,000 and Merck’s experimental antiviral pill for COVID-19 is about $700 per course. Some experts predict various treatments eventually will be used in combination to fight the coronavirus.

Researchers tested the antidepressant in nearly 1,500 Brazilians recently infected with coronavirus who were at risk of severe illness because of other health problems, such as diabetes.