In 2020, a Chinese virologist fled to the United States, aided by allies of President Trump who sought to promote her unproven theories about the origins of Covid-19. Her husband still can’t find her.

© Shannon Stapleton/Reuters

The health secretary has walled himself off from government scientists and empowered fellow activists to pursue his vaccine agenda.

© Haiyun Jiang/The New York Times

In tweaking its chatbot to appeal to more people, OpenAI made it riskier for some of them. Now the company has made its chatbot safer. Will that undermine its quest for growth?

© Julia Dufosse