What we know about the search for a COVID-19 vaccine -- and what we don't

The question of when a COVID-19 vaccine might be available is perhaps the most pressing in the world. There have been a number of recent headlines on this front, including early but encouraging results from trials. And on Wednesday, the Trump administration awarded a contract to Pfizer and a German biotech firm to potentially deliver doses this year. Miles O’Brien joins Judy Woodruff to discuss. Stream your PBS favorites with the PBS app: https://to.pbs.org/2Jb8twG Find more from PBS NewsHour at https://www.pbs.org/newshour Subscribe to our YouTube channel: https://bit.ly/2HfsCD6 Follow us: Facebook: http://www.pbs.org/newshour Twitter:   / newshour   Instagram:   / newshour   Snapchat: @pbsnews Subscribe: PBS NewsHour podcasts: https://www.pbs.org/newshour/podcasts Newsletters: https://www.pbs.org/newshour/subscribe