Gates and his wife, Melinda, released their eponymous foundation’s annual letter Tuesday and said in new interviews this week that helping to improve the health of the poorest people in the world should continue to be a priority of the U.S. government.

“Our letter is being released amid dramatic political transitions in these countries, including new leadership in the United States and the United Kingdom,” they wrote. “We hope this story will remind everyone why foreign aid should remain a priority—because by lifting up the poorest, we express the highest values of our nations.”

Bill Gates told USA Today that foreign policies that put America’s interests above any other nation could threaten health advancements in countries like Africa, which his foundation has aided.

“If you interpret America First in certain ways, it would suggest not prioritizing the stability of Africa and American leadership” the Microsoft co-founder said. “With this new crowd, and with some of things they want to do fiscally, it just means we’re going to have to tell the story of how amazing this work is.”

And in an exclusive column for Fortune’s Most Powerful Women Tuesday, Melinda Gates stressed the importance of contraceptives in her own life and the lives of women who have been helped by the Gates Foundation.

Correction: An earlier version of this story incorrectly said Melinda Gates joined Bill Gates in warning that an “America First” vision could pose a threat to global health initiatives.