A field hospital tent stands outside the emergency department of the Martin Luther King Jr. Community Hospital earlier this month in Los Angeles. California is returning to a tiered restriction system. Patrick T. Fallon/AFP via Getty Images hide caption

A volunteer receives a shot as part of a COVID-19 vaccine trial at Soweto's Chris Sani Baragwanath Hospital outside Johannesburg, South Africa, on Nov. 30, 2020. Jerome Delay/AP hide caption

A woman receives the COVID-19 vaccine last week at Gillette Stadium in Foxborough, Mass. Setting up community vaccination centers will be a key to getting the vaccine to millions, an adviser to President Biden says. Scott Eisen/Getty Images hide caption

Amazon cut off Parler from its Web hosting service, knocking the social media site offline. Hollie Adams/Getty Images hide caption

First Platoon: A Story of Modern War in the Age of Identity Dominance, by Annie Jacobsen Dutton hide caption

In an NPR interview, Republican Sen. Ben Sasse of Nebraska said the U.S. Capitol "was ransacked by a mob that was incited by the president of the United States." Kevin Dietsch/Pool/AFP via Getty Images hide caption

Jack Ma, the billionaire founder of Chinese Internet giant Alibaba, hasn't been seen in public in months after criticizing government regulators. Philippe Lopez/AFP via Getty Images hide caption

Trump supporters clash with police and security forces as they invade the U.S. Capitol on Wednesday. Roberto Schmidt/AFP via Getty Images hide caption