The CDC just rolled back its guidance that vaccinated people could safely go maskless indoors. COVID breakthrough infections are becoming more common as the Delta variant spreads quickly. So how should people be thinking about public health and risk management these days? On today's show, Dara Kass, MD, emergency medicine physician at the Columbia University Medical Center, explains why it's happening (and why you shouldn't panic), and what to do if you are vaccinated and become infected anyway.