Dr. Michelle Chester holds a vial of the Pfizer-BioNTech Covid-19 vaccine at Long Island Jewish Medical Center in the Queens borough of New York City on Monday, December 14. | Lev Radin/Pacific Press/LightRocket via Getty Images

Vox reporter Umair Irfan joins Today, Explained to discuss the latest Covid-19 vaccine news.

It’s been a busy week in vaccine news: The FDA authorized the first Covid-19 vaccine in the US on December 11, and the vaccination campaign is underway. The first US health workers received the Pfizer/BioNTech Covid-19 vaccine on December 14.

With all of the news around coronavirus vaccines, of course, comes a lot of questions. Vox science reporter Umair Irfan joined Today, Explained in a live conversation with host Sean Rameswaram to answer some of the biggest questions from our podcast listeners. (A transcript of their conversation, lightly edited for length and