Researchers who have discovered why the drug Remdesivir is effective in treating the coronaviruses that cause Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) expect it might also be effective for treating patients infected with the new COVID-19 strain. Studied showed that Remdesivir essentially mimics one of the natural building blocks for RNA synthesis necessary for genome replication of the virus. Enzymes within the virus are synthesizing the viral RNA genome with these building blocks, but they mix up the bits they need with the drug. Once the drug is incorporated into the growing RNA chain, the virus can no longer replicate.