Day 244: Pfizer says its Covid vaccine is safe and effective on kids 5-11

<p>Pfizer has released data the company says shows a lower dose Covid vaccine is safe and effective on children ages 5-11. Plus, Biden is preparing to speak to the United Nations for the first time as president. MSNBC's Brian Williams is joined by Philip Rucker, Yamiche Alcindor, Dr. Céline Gounder, Dr. Scott Gottlieb, David Plouffe, and Tim Miller.</p>