Biden's Straight-Talking CDC Director Has Long Used Data To Save Lives

In early December, Dr. Katy Stephenson was watching TV with her family and scrolling through Twitter when she saw a tweet that made her shout.

"I said 'Oh my God!' " she recalls. "Super loud. My kids jumped up. My husband looked over. He said, 'What's wrong, what's wrong, is everything OK?' I was like, 'No, no, it's the opposite. It's amazing. This is amazing!' "

Dr. Rochelle Walensky had just been tapped to lead the Centers for Disease Control and Prevention.