The U.S. has been a global leader in researching, treating and combating infectious diseases around the globe. Today, in honor of World Health Day, let’s look back at some of America’s global health success stories.

PEPFAR, or the President’s Emergency Plan for AIDS Relief, is one of the largest international initiatives by a country to combat a single disease. In 2015, PEPFAR supported HIV counseling and testing for more than 68 million people across the globe, and provided life-saving medications to more than 9 million people.

The effects trickle down to future generations: for every 1,000 people PEPFAR supports with HIV/AIDS treatment, it prevents nearly 450 children from becoming orphaned. In 2015 alone, PEPFAR treatment prevented HIV infection in 267,000 babies who would have otherwise been born with the disease.

The Bipartisan Policy Center found that PEPFAR’s success extends beyond its public health achievements: PEPFAR countries have more positive opinions about the U.S. than the global average, and have also improved socio-economic development more quickly than non-PEPFAR countries.

The President’s Malaria Initiative (PMI) has also been instrumental in reducing malaria deaths, particularly in sub-Saharan Africa. In PMI-supported countries, mortality rates for children under five have dropped significantly: 55 percent in Senegal and Zambia, and 50 percent in Rwanda.

U.S. based nonprofits, like the Bill and Melinda Gates Foundation, have been key partners in fighting malaria. In 2014, the organization contributed more than $150 million to PATH’s Malaria Vaccine Initiative, and recently partnered with the UN to present the goal of eradicating malaria by 2040. And Seattle and D.C. based Malaria No More has worked on the ground in Senegal, Cameroon, South Africa and Zambia to distribute mosquito nets, promote malaria education and, through its Power of One campaign, deliver more than 2 million malaria treatments.

American leadership has been critical to the fight against HIV/AIDS, malaria, and other infectious diseases around the world. As Washington Post columnist Michael Gerson has noted:

“In much of sub-Saharan Africa, the American image is now defined by the Peace Corps, by PMI and by PEPFAR, the American AIDS relief plan. It is a form of influence that is hard to measure or weigh. But people remember when you help to save their children.”

For more on World Health Day, check out the World Health Organization.