This week, hosts Mark Masselli and Margaret Flinter speak with Dr. Naor Bar-Zeev, Deputy Director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health. He examines the scientific guidelines governing COVID-19 vaccine phase 3 clinical trials, including a broad demographic representation to ensure vaccine safety across multiple populations, and the need to address vaccine hesitancy as well as the global supply chain needed to distribute billions of doses.