IE 11 is not supported. For an optimal experience visit our site on another browser.

Shelter-in-place starts in S.F. but could become nation policy

04:14

Dr. Ian Lipkin, director of the Center for Infection and Immunity at Columbia University's Mailman School of Public Health, talks with Rachel Maddow about the effectiveness of social distancing, shelter-in-place, and other policies to control the spread of the novel coronavirus.