Harvard has played a major role in shaping Greater Boston into a global biomedical hub, with overlapping schools, hospitals, and firms that offer state-of-the-art facilities and lifesaving medical research.

But for decades, many of the same institutions have also dispatched hundreds of doctors, researchers, and students to the poorest parts of the planet — where what would be routine care in Longwood often becomes a coin flip.

Even with hundreds of grants terminated or on hold, these efforts continue. But the work sits uneasily in a moment when U.S.-sponsored foreign aid has fallen into disfavor.

As faculty director of the Harvard Global Health Institute, Louise Ivers has been thinking hard about how to defend some of the University’s most altruistic work in a climate of skepticism.

That kind of rhetoric doesn’t come naturally to Ivers. “I don’t work in global health because I think it’s good for Americans, or because of the ‘return on investment’ — not in those terms at all,” she said. “I do it because I believe in a shared humanity, and in global solidarity, and because I think it is our responsibility.”

Nevertheless, she said, there is an argument to be made — one she links to the late Paul Farmer, her friend and mentor and a legend at Harvard and in global health.

“Paul [Farmer] thought Harvard’s physicians, who work in the best-resourced institutes in the country, should also work in the most under-resourced communities in the world. Wrestling between those two experiences can improve both of them.”

Louise Ivers, faculty director of the Harvard Global Health Institute

Starting around 2003, Ivers forged a bond with Farmer in central Haiti, at clinics run by Partners In Health, the organization he co-founded. There, Ivers — an infectious-disease specialist born and educated in Ireland — contended with waves of HIV and tuberculosis even as she provided the day-to-day care demanded by malnutrition and extreme poverty.

“Paul thought Harvard’s physicians, who work in the best-resourced institutes in the country, should also work in the most under-resourced communities in the world,” she said. “Wrestling between those two experiences can improve both of them.”

The nation’s COVID response is a case in point.

In the early months of the pandemic, Massachusetts turned to Partners In Health to provide contact tracing, based on “what the organization had learned working in places like Haiti, with the cholera outbreak, or illnesses like Ebola in West Africa,” Ivers said.

And doctors who have worked in bare-bones clinics across the Global South learn to do more with less — as they had to do in 2020, when ventilators, masks, and diagnostic tests were in short supply worldwide. The work leaves them humbled.

“In Haiti, I learned how necessary it was not to try to force things on the community that they didn’t help come up with,” Ivers said. She learned Haitian Creole, visited patients’ homes, and gave comfort to families grieving children lost to malnutrition or disease.

So as American healthcare becomes more inclusive, she said, we all owe a debt to Haiti.

Today Ivers occupies a multifaceted role like the one Farmer held before his death in 2022: She is a clinician and researcher in Haiti and Africa, a central node in a network of Harvard-affiliated doctors and their partners around the world, and an evangelist for their work at home.

Each month, HGHI hosts virtual conversations that aim to clarify what global health is — and isn’t. For instance, they note, foreign aid accounts for about 1 percent of U.S. annual spending, not the 20 or 30 percent people sometimes estimate it to be.

Even amid attacks on American health programs such as USAID and PEPFAR, global health remains the most popular secondary field among Harvard undergrads, Ivers said.

And many medical students and younger professors of medicine are carrying the work forward.

Like Ivers, Amir Mohareb is an infectious disease specialist. He divides his time between rotations at Mass General Hospital and far-flung zones of global need. The “wrestling” can be painful, Mohareb said. “When we’re overseas, treating someone, we’ll think, ‘I could treat this at home, we could save this person’s life. Here we can’t.’”

But it is also productive. In just the past five years, alongside his frontline care, Mohareb has published dozens of research articles on subjects like oil spills, prison outbreaks, and the deadly risks of migration through Central and South America.

Recently, his work took him to the Darién Gap, on the Panama-Colombia border.

“It’s a region of dense rainforest, and it’s extremely dangerous,” Mohareb said, citing mosquito-borne infections, cartel violence, and unpredictable weather. “But up until this year, probably, people have been migrating through it, in the hundreds of thousands” annually en route to the United States.”

In a 2023 article for The Lancet, Mohareb and Panamanian colleagues gauged the consequences. They used 138 autopsies — a small sample, Mohareb said — to reconstruct the lives of migrants lost in the gap. They found many young adults — but also children and the elderly; Haitian and Ecuadorian migrants were flanked by others from far-off Africa.

Through his research, Mohareb hopes to resurface stories that many in the West aren’t told — or don’t want to hear.

Being a doctor always struck him as a “sacred privilege,” he said. But research strikes him as a privilege, too, offering another kind of relief to its subjects.

“People are sharing vulnerable, sensitive information, and — when the projects are done right — they feel validated and affirmed in their perceptions: that this is happening, not just happening to me.”