Millions of doses of the Pfizer-BioNTech vaccine, just days ago granted emergency use authorization by the FDA, are being distributed across the country. It's the first widely-available vaccine to use something called mRNA technology. So, with the help of epidemiologist Rene Najera, Maddie explains the science behind this vaccine and how it was developed so quickly.

Email the show at shortwave@npr.org.

Learn more about sponsor message choices: podcastchoices.com/adchoices

NPR Privacy Policy