This morning in Savannah, Georgia, the first volunteer was injected in a phase-three vaccine trial administered by Moderna and the National Institutes of Health. Dr Anthony Fauci hopes that up to 15,000 volunteers will be in place by the end of the week. (Tens of thousands more will be needed for additional vaccine trials.) It will take months to learn if the vaccine produces an effective immune response. Scientists who've studied antibody reactions in coronavirus patients have reason to be optimistic, at least in the short-term. And Dr Elke Webber, psychology professor at Princeton University, explains why the pandemic may be getting too big to wrap our heads around. Find and support your local public radio station.Email us at considerthis@npr.org.