Jerome H. Powell, the Federal Reserve chair, stressed on Thursday that even as economic prospects look brighter in the United States, getting the world vaccinated and controlling the coronavirus pandemic remain critical to the global outlook.

“Viruses are no respecters of borders,” Mr. Powell said while speaking on an International Monetary Fund panel. “Until the world, really, is vaccinated, we’re all going to be at risk of new mutations and we won’t be able to really resume activity with confidence all around the world.”

While some advanced economies, including the United States, are moving quickly toward widespread vaccination, many emerging market countries lag far behind: Some have administered as little as one dose per 1,000 residents.

Mr. Powell joined a chorus of global policy officials in emphasizing how important it is that all nations — not just the richest ones — are able to widely protect against the coronavirus. Kristalina Georgieva, the managing director of the International Monetary Fund, said policymakers needed to remain focused on public health as the key policy priority.

“This year, next year, vaccine policy is economic policy,” Ms. Georgieva said, speaking on the same panel as Mr. Powell. “It is even higher priority than the traditional tools of fiscal and monetary policy. Why? Without it we cannot turn the fate of the world economy around.”

Still, she also warned against pulling back on monetary policy support prematurely, saying that clear communication from the United States is helpful and important. The Fed is arguably the world’s most critical central bank thanks to the widely used dollar, and unexpected policy changes in the United States can roil global markets and make it harder for less developed economies to recover.

“Premature withdrawal of support can cut the recovery short,” she cautioned.

The Fed has held interest rates near zero since March 2020 and has been buying about $120 billion in government-backed bonds per month, policies meant to stoke spending by keeping borrowing cheap. Officials have been clear that they will continue to support the economy until it is closer to their goals of maximum employment and stable inflation — and that while the situation is improving, it is not there yet.

“There are a number of factors that are coming together to support a brighter outlook for the U.S. economy,” Mr. Powell said, noting that tens of millions of Americans are now fully vaccinated, so the economy should be able to fully reopen fairly soon. “The recovery though, here, remains uneven and incomplete.”

Employers added more than 900,000 workers to payrolls last month, but the country is still missing millions of jobs compared with February 2020 and fresh data showed that state jobless claims climbed last week. Mr. Powell pointed out that the burden is falling heavily on those least able to bear it: Lower-income service workers, who are heavily minorities and women, have been hit hard by the job losses.

When asked what keeps him awake at night, Mr. Powell said that “there’s a pretty substantial tent city” he drives past on his way home from work in Washington. “We just need to keep reminding ourselves that even though some parts of the economy are just doing great, there’s a very large group of people who are not.”

Given the pandemic’s role in exacerbating inequality, both Mr. Powell and Ms. Georgieva said it was critical to support workers and make sure they can find their way into new and fitting jobs.

The Fed chair said policy tended to focus too much on short-term, palliative measures and not enough on longer-term solutions that help to expand economic possibility.

“I think we need to, really as a country — and I’m not talking about any particular bill — invest in things that will increase the inclusiveness of the economy and the longer-term potential of it,” Mr. Powell said. “Particularly invest in people, so that they can take part in, contribute to and benefit from the prosperity of our economy.”

Those comments come as the Biden administration is pushing for an ambitious $2 trillion infrastructure package that would include provisions for labor market training, technological research and widespread broadband. The administration has proposed paying for the package by raising corporate taxes.

“For quite some time, we have been in favor of more investment in infrastructure. It helps to boost productivity here in the United States,” Ms. Georgieva said, calling climate-focused and “social infrastructure” provisions positive. She said they had not had a chance to fully assess the plan, but “broadly speaking, yes, we do support it.”

But the White House’s plan has already run into resistance from Republicans and some moderate Democrats, who are wary of raising taxes or engaging in another big spending package after several large stimulus bills.

Some commentators have warned that besides expanding the nation’s debt load, the government’s virus spending — particularly the recent $1.9 trillion stimulus package — could cause the economy to overheat. Fed officials have been less worried.

“There’s a difference between essentially a one-time increase in prices and persistent inflation,” Mr. Powell said on Thursday. “The nature of a bottleneck is that it will be resolved.”

If price gains and inflation expectations moved up “materially,” he said, the Fed would react.

“We don’t think that’s the most likely outcome,” he said.