This is a difficult time in global health. My barometer for optimism can be distilled to a simple question: Did fewer kids die this year compared to last year? In 2025, for the first time this century, that number went up to 4.8 million, from 4.6 million the year before—an increase driven, in part, by cuts to health aid.

Immunizing children and supporting other health-related efforts—like fighting malaria, HIV, and tuberculosis—is the biggest focus of my philanthropy. I’m moved to act by the fact that the vast majority of childhood deaths happen in poor countries. Meanwhile, lifesaving tools like vaccines and medicines get developed for diseases that affect those who can pay, and not for ones that mostly affect people in poorer countries.

These setbacks are coming at a time when science is giving us unprecedented tools for fighting disease. For example, it’s now possible to envision the end of AIDS as a global threat to health—an idea that I thought was out of reach just a few years ago.

As a grandfather, I can’t imagine how awful it would be to lose a child, yet millions of families suffer that tragedy every year simply because of where they live. Fixing this disparity is the chief reason the Gates Foundation exists. I go to work each day thinking about how I can help close the gap.