Political tides have turned in the United States and in the UK. Tech titan and philanthropist Bill Gates is worried that the big shifts happening at home and across the pond may endanger global health.

The Microsoft cofounder and his wife Melinda have expressed their concerns as President Donald Trump's America First policy takes full swing and as Britain's new Prime Minister Theresa May takes the helm.

Global Health As National Interest

With the U.S. government and Britain taking a more inward-looking stance, the billions of foreign aid critical to helping poor countries prevent deaths among children, the sick, and the marginalized could be cut.

"If you interpret America First (the stated doctrine of President Trump) in certain ways, it would suggest not prioritizing the stability of Africa and American leadership. With this new crowd, and with some of they want to do fiscally, it just means we're going to have to tell the story of how amazing this work is," Bill Gates said in an interview with USA Today.

The Bill & Melinda Gates Foundation, which spends billions to help prevent deaths in poor countries and help find cure to different diseases, will have a tougher time doing its job.

"Governments have to look outward. The message we are giving is, we are a global community. Ebola came here. When we help the world, peace and security also up on our doorstep," Melinda Gates told USA Today over the phone.

Melinda added that their work with the foundation aims to do the right things for people in several aspects including health. They primarily do their work to help people out of poverty.

In their 2017 Annual Letter, Bill and Melinda Gates expressed their worries.

"We hope this story will remind everyone why foreign aid should remain a priority, because improving lives abroad is in our own national interest as well as the world's," they wrote.

They also listed favorite numbers to highlight how the foundation is achieving its goals. Since 1990, for example, 122 million children have been saved, driving mortality rates of kids under 5 down.

The philanthropic work of Bill and Melinda has also contributed to providing basic vaccines to 86 percent of children across the globe.

The letter also covered newborn mortality, malnutrition, family planning, and poverty. Ultimately, the foundation of the power couple wants to achieve their magic number - zero. They want to see zero cases of malaria, TB, HIV, malnutrition and preventable deaths.

"Zero difference between the health of a poor kid and every other kid," a portion of the letter reads.

With the America First policy, Bill Gates is worried that promises, such as to bring affordable HIV drugs to people, might not be delivered. He is hoping that Trump was convinced during their recent meeting but is pessimistic if he was able to get the message across that the United States has an important role in keeping healthy and stable Third World countries.

"The budget is particularly tight, people are talking about increasing defense (spending), lowering taxes, interest costs will be higher," he says. "So when you look at it mathematically you say, 'Will the saving of millions of lives for less than $100 a year of drugs, will the U.S. continue to do that?' It's not clear where we're headed," he said.

America First Policy As A Big Wall To Foreign Aid

Trump's global gag rule is seen as an attack to health care for women across the globe. It basically blocks U.S. funds to organizations involved in abortion advice and care in other countries.

"We're concerned that this shift could impact millions of women and girls around the world. It's likely to have a negative effect on a broad range of health programs that provide lifesaving treatment and prevention options to those most in need," Melinda Gates said in an interview with The Guardian.

However, the policy of the U.S. government goes beyond family planning and may affect programs that help treatment and eradication of HIV, malaria, and TB worldwide.

"The [United States] is the No. 1 donor in the work that we do. Government aid can't be replaced by philanthropy. When government leaves an area like that, it can't be offset, there isn't a real alternative. This expansion of this policy, depending on how it's implemented, could create a void that even a foundation like ours can't fill," Bill Gates explained.

Bill and Melinda Gates pledged to give away more than 99 percent of their wealth. With most of it going to good causes, public health as a matter of politics will surely make it difficult for them to achieve what they want.