Explainer: What Is Remdesivir and How Does It Treat COVID-19?

BALTIMORE — SARS-CoV-2, the virus that causes COVID-19, is an RNA virus. This means the coronavirus uses nucleosides as the building blocks of its genetic material, according to University of Maryland, Baltimore County biochemist Katherine Seley-Radtke.

Writing for media outlet The Conversation, Seley-Radtke says the virus relies on an enzyme called polymerase to replicate its RNA nucleoside by nucleoside, so that it can make more copies of itself.

Gilead's remdesivir is an antiviral and a nucleoside analogue, or a chemical compound that is structurally similar to naturally occurring nucleosides. During replication, remdesivir could trick the polymerase into mistaking the antiviral drug, which resembles adenosine, for the genuine article.

After this happens, the antiviral is taken into the new RNA strand and stops the polymerase from replicating more of the RNA, which should suppress the virus. Preliminary results from May suggest the drug improved patient survival rate and time recovery.