Jonathan Bastian talks with Meghan O’Rourke, writer, poet, and author of “The Invisible Kingdom: Reimagining Chronic Illness,” about her 11-year search to find out what was wrong with her. Later, David Agus, professor of medicine and CEO of the Lawrence J. Ellison Institute for Transformative Medicine at the University of Southern California, explains autoimmune disease, long COVID, and what the future holds for diagnosis and treatment.