It didn’t matter that Citigroup paid Amy Wu Stratton $450,000 in 2021 — her most lucrative year ever — to work with some of its biggest private equity clients. It didn’t even matter that she was on track for a promotion that could double her pay.

After almost 16 years in banking, she was ready for something new.

“I was just so tired of it. It wasn’t making me happy,” said Ms. Stratton, 45, a former director in a Citi division that worked on financing and risk management for deals. A job she loved had become a hamster wheel, she said — an unfulfilling chase for more money and promotions.

“You don’t have time to breathe,” she said. “The pandemic slowed me down and made me take stock.”

Up and down Wall Street, droves of bankers are changing jobs — switching banks, moving to investment firms, taking equity stakes in financial technology companies or cryptocurrency start-ups — and sometimes getting out altogether. Pandemic-inspired ennui, blockbuster profits and a war for talent across the industry has accelerated the job churn at the country’s big banks.

“People are exhausted,” said Alan Johnson, the managing director of Johnson Associates, a Wall Street compensation consultancy. The ranks of those earning $10 million or more will grow amid competition for top performers after a bumper year for earnings, Mr. Johnson said, but “money doesn’t always make you happy.”

Ms. Stratton left Citi in June, moved by social upheaval: the Black Lives Matter protests, the Jan. 6 riot at the U.S. Capitol and an increase in anti-Asian attacks. She and two partners are developing a website, myasianvoice.com, for Asian women who are focused on careers and social impact.

It was an obvious choice, said Ms. Stratton, a Chinese immigrant whose Upper East Side co-op and Wall Street rewards had already exceeded her humble upbringing in a rural village that lacked running water.

“I was so happy to get out of that thinking of always having more and more,” she said.

Itchy feet have forced big banks to open their wallets: The combined compensation costs the nation’s six largest lenders rose 12 percent to nearly $178 billion in 2021.

Goldman Sachs gave special stock awards to about 30 top executives and some 400 partners to help retain them. Bank of America bumped up salaries for thousands of senior and midlevel investment bankers and handed out stock awards to its rank-and-file. Even junior analysts across the industry have seen their typical base pay rise to $100,000 or more, from about $85,000.

In many cases, the banks are fighting among themselves for talent. Sarah Youngwood, the finance chief for JPMorgan Chase’s consumer-banking division since 2016, will become chief financial officer at the Swiss bank UBS in May. She’ll join an executive team whose members made an average of $9.5 million in 2020, according to UBS’s most recent compensation report.

Other bankers who are moving to rivals spoke on the condition of anonymity because of the sensitivity of the matter. One sacrificed his bonus to leave, but the new firm covered his lost earnings and gave him a role with more responsibility. Another with decades of experience was lured away by a competitor to build a new business, shedding what he felt was the frustrating bureaucracy of his old firm.

But the wealth of opportunities extends well beyond direct competitors.

Stephen M. Scherr, who left his post as finance chief at Goldman Sachs at the end of December, quickly pivoted to the helm of Hertz. He earned $38 million in 2019 and 2020, even after being docked $7 million for Goldman’s role in raising money for a Malaysian sovereign wealth fund looted by a former prime minister and his inner circle. At Hertz, Mr. Scherr will get a base salary of $1.5 million and more than 12 million shares of company stock that vest over several years if he meets targets.

Sayena Mostowfi, 44, took over as president of the Long-Term Stock Exchange, an upstart equities exchange, this month. Ms. Mostowfi, a former global chief operating officer of electronic equities at Citi, said she had jumped at the chance to build a new business.

“What’s great about working at a smaller company is there’s a direct correlation between the effort that you put into the work that you’re doing and the results that you get,” she said. “I’m willing to bet that being at a start-up will bring better results for me than being at a bank.”

Booming markets have given wandering bankers plenty of money to fall back on, said Roosevelt D. Bowman III, a senior investment strategist at the asset manager AllianceBernstein.

Mr. Bowman said midcareer professionals who had led business units and made millions of dollars a year had “already hit the first home run,” making it easier to take a risk. “There is so much wealth being created in so many different ways,” he said.

Michael Litt, chief executive of Vidyard in Waterloo, Ontario, is recruiting an investment banker for a senior role at his 300-person video messaging company. Such deal makers can be assets because they have “incredible work ethic and focus,” Mr. Litt said.

In return, he can offer equity and the greater influence that comes with working at smaller firm. Another perk that’s rare on Wall Street: Work where you want. One Vidyard executive, Mr. Litt said, lives in a boat docked off Los Angeles.

Tim Shea left Truist Securities to open a Chicago office for the boutique investment bank Solomon Partners in September. Alongside another managing director, Mr. Shea has hired two vice presidents, two associates, an analyst and summer interns. He is also in late-stage talks to hire senior bankers, and expects his team to grow to about 20 people by the end of the year.

Those candidates can count on good treatment because of the hot job market. If new hires left money on the table at their old job, like a pending bonus or deferred compensation, they can “expect to be made whole,” Mr. Shea said.

Prospective employees are thinking more deeply about their careers, knowing they’re going to be putting in long hours, he said. They’re wondering, “How can I make that as meaningful as possible and feel good about it?” he said.

Big paydays are still a powerful draw, of course. Just two years ago, Steven G. Eckhaus, a Wall Street employment lawyer at McDermott Will & Emery who represents top bankers in job talks, locked in a $20 million signing bonus for a client after a four-month bidding war. It was an eye-watering amount then, but Mr. Eckhaus has negotiated a handful of similar packages in the last few months with little fanfare.

“These guys are real good poker players — in the end, everybody shows little emotion,” Mr. Eckhaus said. “They feel they’re getting what they should.”

This year’s job-hopping season isn’t even in full force — bonuses often land in mid-February, and stock awards in March — but plenty of heavy hitters made the jump in 2021, too.

Gregg Lemkau, who co-led Goldman’s investment banking division, left to be chief executive of MSD Partners, which manages more than $20 billion for the Dell Technologies founder Michael Dell and others. Jack MacDonald, Bank of America’s former co-head of global investment banking, left to join the boutique investment bank Centerview Partners. And a former head of Goldman’s Marcus consumer unit, Omer Ismail, moved to Hazel, a fintech start-up backed by Walmart that will be rebranded One.

At the executive recruiting firm True Search, demand for fintech candidates rose more than 200 percent last year, said Grant Beighley, who leads searches for the company’s fintech clients. October was the busiest month in the history of its financial-services practice, with more than 60 new searches.

And many bankers, Mr. Beighley said, are in the market to try something different.

“They’re tired of feeling like a cog in a machine,” he said.

Johnson & Johnson’s easy-to-deliver Covid-19 shot is the vaccine of choice for much of the developing world.

Yet the American company, which has already fallen far behind on its deliveries to poorer countries, late last year quietly shut down the only plant making usable batches of the vaccine, according to people familiar with the decision.

The facility, in the Dutch city of Leiden, has instead been making an experimental but potentially more profitable vaccine to protect against an unrelated virus.

The halt is temporary — the Leiden plant is expected to start churning out the Covid vaccine again after a pause of a few months — and it is not clear whether it has had an impact on vaccine supplies yet, thanks to stockpiles.

But over the next several months, the interruption has the potential to reduce the supply of Johnson & Johnson’s Covid vaccine by a few hundred million doses, according to one of the people familiar with the decision. Other facilities have been hired to produce the vaccine but either aren’t up and running yet or haven’t received regulatory approval to send what they’re making to be bottled.

Inside Johnson & Johnson’s executive suites, the decision to suspend production at Leiden prompted concerns that it would impair the company’s ability to deliver on its vaccine commitments to the developing world.

Johnson & Johnson’s move also blindsided officials at two of the company’s most important customers: the African Union and Covax, the clearinghouse responsible for getting vaccines to poor countries. Leaders of those organizations learned of the halt in production from New York Times reporters.

“This is not the time to be switching production lines of anything, when the lives of people across the developing world hang in the balance,” said Dr. Ayoade Alakija, a co-head of the African Union’s vaccine-delivery program.

Jake Sargent, a spokesman for Johnson & Johnson, said in an email that the company was “focused on ensuring our vaccine is available where people are in need” and that its global production network “is working day and night” to help fight the pandemic.

He said the company was continuing to deliver batches of the vaccine to facilities that bottled and packaged doses. He also said Johnson & Johnson had millions of finished doses in inventory.

Johnson & Johnson’s Covid vaccine, initially billed as a single shot, fell out of favor in the United States and other wealthy countries in part because of its link to a rare but dangerous blood-clotting disorder. Studies have found that it performs worse by some measures than the shots from Pfizer and Moderna.

But poorer countries remain reliant on Johnson & Johnson’s vaccine, which does not require ultracold refrigeration. It has been shown to provide strong and long-lasting protection against severe disease across variants, including Omicron, when given as a two-shot regimen. As a single shot, the vaccine is less expensive and relatively easy to give to hard-to-reach populations.

“In many low- and middle-income countries, our vaccine is the most important and sometimes only option,” Dr. Penny Heaton, a Johnson & Johnson executive, said in December at a meeting of experts advising the U.S. government on vaccines. She added, “The world is depending on us.”

Lower-income countries now have more vaccine options than at any previous point in the pandemic, and the impact of pausing production at the Leiden plant is therefore less severe than it might have been in the past. Some African governments have asked vaccine manufacturers to pause shipments until the countries use what they have on hand. Companies have cited that as evidence that they are providing plenty of vaccines to poorer countries.

But the reality is more complicated.

Only about 11 percent of Africans have been fully vaccinated (and few have received boosters). Many countries lack the infrastructure — medical personnel, storage facilities and transportation — to quickly inoculate their populations. They don’t need a huge pile of vaccines all at once; they need a steady and predictable supply over many months.

As recently as last summer, Johnson & Johnson had projected that it would deliver one billion doses of its Covid vaccine in 2021. The company badly missed that target, releasing roughly 400 million doses, according to a person familiar with the company’s vaccine production.

Mr. Sargent said the company was continuing to fulfill its contractual obligations to the African Union, which has ordered vaccines on behalf of dozens of countries in Africa and the Caribbean, and to Covax, which buys vaccines for scores of low-income governments.

But Johnson & Johnson failed to deliver anywhere near as many doses to Covax as it planned. The company said in May that it “aimed to supply” up to 200 million vaccine doses to Covax by the end of last year. Covax got only four million; another 151,000 arrived last month, according to Gavi, the main nonprofit that runs Covax. (Wealthy countries supplemented that with donations.)

The African Union, which ordered 220 million doses, has fared better. It has been receiving doses on or ahead of schedule, with the bulk of the order due in the next eight months.

Dr. Seth Berkley, who helps run Covax as the chief executive of Gavi, said the Johnson & Johnson vaccine had been at the center of the program’s strategy for fighting Covid last year. But because of Johnson & Johnson’s delay in delivering doses, Covax has increasingly looked to other vaccine providers.

“We really needed their doses in 2021, and we were counting on them,” Dr. Berkley said. “They didn’t deliver. So we had to find other doses to meet the countries’ needs.”

An African Union official said the bloc was also concerned by the decision to pause production at the Leiden plant because it had been assured that all of its vaccine would come from that facility. The official said Johnson & Johnson’s move raised doubts about whether the bloc would exercise an option to buy an additional 180 million Johnson & Johnson doses.

Johnson & Johnson has already faced criticism for failing to prioritize people in developing countries for its Covid vaccine. Last summer, the head of the World Health Organization rebuked the company after The Times reported that millions of doses that had been bottled in South Africa were being exported for distribution in Europe.

To make its Covid vaccine, Johnson & Johnson relies on a sprawling international network. In addition to the company-run Leiden facility, factories in India, Baltimore and North Carolina have been hired to make the substance of the vaccine. Others, including a plant in South Africa, handle the so-called fill-finish process of bottling and packaging doses.

From the start, Johnson & Johnson executives told U.S. officials that they planned to eventually pull the Leiden facility out of the rotation so it could make other products, according to current and former U.S. officials.

That was before Johnson & Johnson’s network was overrun with problems.

Johnson & Johnson hired a contractor, Emergent BioSolutions, to produce its vaccine at a Baltimore plant that is big enough to make the equivalent of up to a billion doses a year. Emergent, however, failed to meet federal manufacturing standards, and regulators forced the plant to suspend production last April.

The factory restarted in August, but regulators with the Food and Drug Administration have not yet determined that it can consistently operate in compliance with manufacturing standards, officials said.

As a result, the F.D.A. has insisted on reviewing individual batches of vaccines before they are shipped to be bottled. Regulators haven’t cleared any batches made since the factory reopened, said Matt Hartwig, a spokesman for Emergent.

Plans are underway for two other facilities — one a Merck plant in North Carolina, the other run by Biological E in India — to start contributing batches of the Johnson & Johnson vaccine. But those plants are not yet producing usable vaccine substance and are not expected to do so until late spring.

The Merck plant — whose participation in the vaccine production the White House last year hailed as a “historic” breakthrough — was supposed to be producing batches as early as last fall. That timeline has since been pushed back to late spring, federal officials said.

The delays at Merck and Emergent increased the importance of the Leiden plant. After a renovation last year, the facility had the capacity to produce the equivalent of well over 50 million Covid vaccine doses a month, said two people familiar with the matter.

Unlike companies such as Pfizer and Moderna, which have reaped billions of dollars in profits, Johnson & Johnson did not find the Covid vaccine to be a big moneymaker.

Johnson & Johnson vowed to sell its vaccine on a not-for-profit basis. The vaccine generated about $2.4 billion in sales last year, less than 3 percent of the company’s total revenue.

Since production of the Covid vaccine was halted late last year, the Netherlands plant has been manufacturing an experimental vaccine against respiratory syncytial virus, or R.S.V., that will be used for a clinical trial in older adults in wealthy countries, a person familiar with the matter said. Even if it proves effective, the vaccine is not expected to become available for several years.

Mr. Sargent, the Johnson & Johnson spokesman, said the company’s manufacturing sites “produce multiple products, as we have an obligation to supply life-changing medicines to patients around the world.”

Johnson & Johnson is among several companies racing to develop the first vaccine for R.S.V., which kills an estimated 14,000 older adults in the United States annually.

As with other medical products, the company that wins the first approval is poised to have an advantage in capturing a big share of a market that some analysts think could be worth $10 billion annually by 2030.

The vaccine is likely to be aimed at people in wealthy countries, since adults in the developing world are rarely tested for R.S.V.

Even with the Leiden plant no longer making the Covid vaccine, Mr. Sargent said Johnson & Johnson continued to provide batches to all of the sites that were handling bottling.

One of those is Aspen Pharmacare in South Africa. Stephen Saad, Aspen’s chief executive, said the Leiden shutdown had not interrupted the supply of vaccine to Aspen’s factory.

Johnson & Johnson is preparing to return the Leiden facility to making the Covid vaccine next month.

But that won’t translate into an immediate gusher of new doses. The facility’s production will undergo testing and inspections. Doses made from the restarted Leiden production most likely won’t be shipped until May or June.