It’s too early to call it a miracle cure, but if the conclusions from a recent Phase 1 trial for a new drug called EXO-C24 are backed up in subsequent trials, we might have the first true breakthrough therapy for COVID-19. That’s in addition to coronavirus vaccines, of course, which will help prevent severe COVID-19 cases and deaths, and even reduce the spread of the illness. But while vaccines can give the immune system a heads-up to the threat it might have to deal with — the real virus — they have a few limitations. First of all, they don’t work on infected people. Secondly, vaccine supply is still limited and vaccinations aren’t available to anybody who might want one. Then there’s the threat of coronavirus mutations that might reduce vaccines’ effect on the virus and extend the pandemic.