 Chad. Okay, I'm Chad Abumrad. This is Radiolab. We're going to go to break, but when we come back, we're going to hear from some of the modern-day heroes who are voluntarily getting infected with COVID in order to help scientists test vaccines. That is coming up. Radiolab is supported by BetterHelp, committed to supporting mental health through therapy. Clients are matched with one of 35,000 therapists and can communicate via video, chat, or phone at betterhelp.com slash public.