Elena received the letter on a Tuesday morning, forwarded from her institute office to her university email. The envelope contained handwritten note from a woman she'd never met, requesting meeting at a vaccination center in rural Kenya. My name is Dr. Amara Kipchoge, the letter read. I trained at your institute three years ago as part of the international fellowship program. I'm now directing vaccination efforts across rural Kenya. There's situation I need your perspective on, but I wanted to see you in person rather than request consultation remotely. Elena studied the letter, trying to place Amara Kipchoge in her memory. The name wasn't immediately familiar, which meant she'd probably been one of dozens of international fellows who'd passed through her institution during the intensive

