Scientists have identified an off-patent drug that can be repurposed to prevent COVID-19 — and may be capable of protecting against future variants of the virus — in research involving a unique mix of ‘mini-organs’, donor organs, animal studies and patients. The research showed that an existing drug used to treat a type of liver disease is able to ‘lock’ the doorway by which SARS-CoV-2 enters our cells, a receptor on the cell surface known as ACE2. Because this drug targets the host cells and not the virus, it should protect against future new variants of the virus as well as other coronaviruses that might emerge.