The breakthrough that transformed the Gates Foundation

We started the Gates Foundation 25 years ago to save and improve children’s lives. But no one can solve a problem they don’t fully understand. And back in 2000, the world’s understanding of childhood mortality was occasionally inaccurate, often imprecise, and almost always incomplete.

That’s why I believe the breakthrough that transformed our foundation in the two-and-a-half decades since wasn’t a single vaccine or treatment—it was a revolution in the world’s understanding of childhood mortality. Through advances in how researchers collect and analyze global health data, we now know much more about what kills children, where these deaths occur, and why some kids are more vulnerable than others. By putting those insights to work, we’ve been able to save lives.

The first challenge was knowing exactly what was killing children.

Reading the 1993 World Development Report opened my eyes to the scale of the problem: Around 12 million children under the age of five were dying every year, with a staggering disparity between rich and poor countries. But the available data was fragmented and inconsistent. That made it difficult to understand trends or allocate resources effectively.

So the foundation helped create the Institute for Health Metrics and Evaluation at the University of Washington, to give a permanent home to the Global Burden of Disease study—originally developed in the 1990s by researchers at Harvard University and the World Health Organization. We wanted to expand it from a static snapshot of the problem into a regularly updated tool that tracked how diseases impact people around the world. That gave us something the world never had before: a comprehensive—and current—picture of child mortality across every country.

Measuring symptom-based causes of children’s deaths was an important step. But broad disease categories like “diarrhea” or “respiratory infection” didn’t give us enough information to act on. We needed to know which specific pathogens were responsible for the most common and fatal cases. So the Gates Foundation funded two landmark studies to find out.

In 2013, the Global Enteric Multicenter Study, or GEMS, found that rotavirus was causing 20 percent of lethal diarrhea cases in kids. At the time, diarrhea was the second-leading infectious killer of children. While oral rehydration therapy had already helped bring down deaths over previous decades, GEMS helped fast-track the rollout of a more targeted tool—a new rotavirus vaccine—in the hardest-hit countries, in close partnership with Gavi, the Vaccine Alliance.

A year later, the Pneumonia Etiology Research for Child Health study, or PERCH, revealed that respiratory syncytial virus, or RSV, was a much more common cause of severe pneumonia—the leading infectious killer of kids around the world—than previously understood. (And not just in low- and middle-income countries, where 97 percent of RSV deaths occur, but in higher-income ones too, where the virus still fills pediatric hospital wards each winter.) That prompted us to expand our investments in RSV prevention, which led to the approval of the first maternal vaccines for RSV in 2023.

But understanding what causes childhood mortality wasn’t enough on its own, because deaths aren’t distributed evenly across countries—or even within them. That’s why our second challenge was to figure out where exactly children were dying.

At the time, most health data was collected at national or regional levels. That masked major differences in disease burden from one community to the next—and made it harder to target interventions effectively.

To solve this second challenge, the foundation invested in new approaches to health mapping that combined satellite imagery, GIS technology, GPS data, and local health surveys. These maps gave Ministries of Health and implementing partners unprecedented, anonymized detail about disease patterns and population distribution, down to individual neighborhoods, that transformed how and where public health resources are deployed—while still preserving the privacy of the individual children and families in these places.

In Pakistan—one of just two countries where wild polio remains endemic—advanced mapping tools have helped vaccination teams reach and protect kids in settlements that weren’t on any official maps. Across sub-Saharan Africa, better geographic data has transformed the fight against malaria by revealing that transmission often clusters in small, hyper-local pockets. Through the Malaria Atlas Project, countries like Nigeria can now track those patterns more precisely—and then get bed nets, testing, and treatment where they’ll have the greatest impact.

With better knowledge of what was killing children, and where, one more fundamental question remained: Why might one child die from a disease while another—who lives in the same place, faces the same risks, and gets the same treatment—survives? This was our third big challenge.

In theory, traditional autopsies would provide the answer. But in the places where most childhood deaths still occur, these invasive procedures are often impossible to perform—too costly, and sometimes opposed for religious, cultural, or personal reasons.

So in 2015, the foundation launched the Child Health and Mortality Prevention Surveillance network, or CHAMPS, which now operates in nine countries across Africa and South Asia. Working with in-country partners, CHAMPS pioneered a new autopsy alternative—using minimally invasive tissue sampling—that can determine causes of death quickly and accurately while respecting local customs and beliefs.

Through CHAMPS, we discovered that childhood deaths rarely have a single cause. Instead, kids often have multiple conditions at the same time, with malnutrition frequently leaving them much more vulnerable to a whole host of infections. (While it rarely shows up on death certificates, it’s an underlying cause of death in nearly half of all child mortality cases.) That finding helped solidify nutrition as a core focus of the foundation’s global health work—and the research, innovation, and product development we invest in. On the ground, we’re supporting partners as they integrate nutrition screening into routine care and train healthcare workers to manage multiple risks at once.

CHAMPS also demonstrated that inadequate prenatal care is responsible for a majority of stillbirths, newborn deaths, and maternal deaths, prompting us to further expand access to maternal health services—like prenatal vitamins and AI-enabled ultrasounds—in the communities where we work.

But the biggest takeaway from CHAMPS is also the most hopeful—and a reminder of why we started the Gates Foundation in the first place: So many childhood deaths could be prevented with existing interventions. We just need to ensure they reach the right children at the right time.

Twenty-five years in, our work on child mortality is far from complete. Still, the impact of what we have learned has been enormous

The Global Burden of Disease, GEMS, and PERCH studies helped shift global priorities by showing the world what was really killing kids—and where new vaccines and treatments could make the biggest difference. Better geospatial tools have empowered countries to pinpoint disease hotspots, find previously unmapped settlements, and distribute life-saving resources where they’re needed most. And CHAMPS is giving governments better data on why children are dying—data that’s now shaping policies, improving reporting, and guiding more effective care.

Most importantly, even as the number of children born every year has gone up, the number of overall childhood deaths has fallen by more than half—from 11.3 million in 1990 to 4.5 million in 2022. Playing a part in making that happen is the best job I’ve ever had, and the most meaningful work I’ve ever done.

At the Gates Foundation, we used to say we could cut child mortality in half again by 2040. The truth, though, is that goal feels further out of reach now—not because the science has stalled, but because support for global health has. The progress we’ve been part of was only possible because governments around the world, including here in the U.S., made long-term commitments to saving lives and followed through. That kind of leadership gave millions of children who would have died a chance at life—and made life better for millions more. 

The last 25 years have shown us what’s possible. The next 25 will depend on whether the world keeps showing up for the children who need it most.