This week marks one year since the first known COVID-19 death. And while the remarkable pace of vaccine development is widely praised, the lag in its distribution is concerning. Only nine million, or one-third, of the total available doses in the United States have made their way into the arms of Americans. What’s causing the delays? Katherine Ellen Foley, health and science reporter at Quartz Health Report, discusses the process with Dr. Florian Krammer, professor of vaccinology at the Icahn School of Medicine at Mount Sinai. Krammer sheds light on many complexities of the current COVID situation, including the latest knowledge on new variants of the virus. Is there enough diversity among the vaccines in terms of how they attack the virus and its mutations? How are scientists working to better understand immunity? How are we approaching the ethical dilemmas of which populations get the shot before others? Krammer shares when we’ll see “serious progress” in the rollout and what it will look like over the coming months.