Vaccination and masking are the safest ways to prevent COVID-19. But epidemiologists warn that when it comes to preventing omicron, all masks are not equal. Infectious disease expert Saskia Popescu explains. And, Angela Stent of Georgetown University talks about the events that led up to the collapse of the Soviet Union 30 years ago. And Masha Gessen of The New Yorker talks about what life was like for people in Russia as it transitioned.