As scientists continue to monitor the impact of the available COVID vaccines, how do our personal equations around risk and safety change? On today's show, Celine Gounder, professor of medicine & infectious diseases at the NYU School of Medicine; Bellevue Hospital doctor, medical analyst for CNN and the host/producer of American Diagnosis and Epidemic podcasts, explains what a CDC study of essential workers found, including confirmation that the vaccines prevent illness from COVID-19 in real-world conditions and that they appear to prevent even asymptomatic infections.