April 9, 2020 -- In the United States and Europe, a handful of clinical trials have begun to test ways to keep health care workers and other vulnerable people safe from COVID-19.

Most are testing drugs called chloroquine or hydroxychloroquine that have long been used to prevent and treat malaria, and also as a therapy against rheumatoid arthritis and lupus. The hope is that, given before infection or early in the course of the disease, the drugs will protect someone against infection and illness from the virus, or, if they do, will ensure that their case is mild.

But whether these drugs will help, hurt or do nothing remains an open question.

Scientists strongly support these trials, but are equally vehement that these drugs should only be used in the context of a clinical trial – to carefully test effectiveness, be on the lookout for any negative effects, and to ensure that there is an adequate supply of the drugs if they prove useful.

“This is a virus that targets health care workers,” because they are in close proximity to very contagious people, says Warner Greene, a senior virologist with the Gladstone Institutes, an independent, nonprofit research organization based in San Francisco. “We have to do everything we can to protect them.”