CNN has reported that a cheap, generic antidepressant drug may reduce the risk of severe getting COVID-19 by close to a third in people at high risk. The data comes from a trial among about 1,500 patients in Brazil showing those who took the drug, known as fluvoxamine, were less likely to progress to severe disease and to require hospitalization.

The drug, sold under the brand name Luvox, is a selective serotonin reuptake inhibitor most often used to treat obsessive-compulsive disorder and depression. But it can affect inflammation, said Dr. Angela Reiersen, an associate professor of psychiatry at Washington University in St. Louis who worked on the study, published in The Lancet Global Health.

“Fluvoxamine may reduce the production of inflammatory molecules called cytokines, that can be triggered by SARS-CoV-2 infection,” CNN quoted Reiersen as saying in a statement. The drug may also reduce blood platelets, which may affect the clotting effects of coronavirus infection.

More study is needed to see if the drug might be added to the treatments given to coronavirus patients, but it’s cheap. “A 10-day course of fluvoxamine costs approximately $4 even in well-resourced settings,” the researchers wrote.

A related drug, Prozac, or fluoxetine, is also cheap and even more widely available, and the researchers said this drug should be studied to see if it might help.