The local economy is on the brink — but of what?

At times, Faneuil Hall Marketplace in Boston was quiet on Wednesday.Craig F. Walker/Globe Staff/file

For restaurant owners like James DiSabatino, it’s the disappearance of the lunchtime rush.

For Bill Sykes, who puts up fencing at parades and road races, it’s a spring calendar canceled.

For Uber drivers like Najib Ssemambo, it’s concerns about a sick passenger in his car, compounded by worries that he won’t have passengers at all.

The quick spread of the coronavirus across Greater Boston in recent days — and the spread of closings and cancellations to try to contain it — is rippling fast through the region’s economy, and giving pause to a place long confident about its prosperity.

Conventions have been canceled and college students have been sent home. People who are allowed to telecommute are figuring out how to do it. People who can’t are pondering how to make a living without risking illness. And the news darkened Wednesday night, when President Trump announced strict travel restrictions from Europe and the NBA put its season on hold. Stock markets, fresh off a tumble Wednesday, appeared poised to fall further Thursday morning.

By and large, the rhythms of life in Greater Boston haven’t changed much yet. Commuters Thursday morning were still riding the T. Office towers still bustled. Bars remained busy. But the contingency planning, the convention-less Seaport, the quiet Kendall Square suggest an economy on the brink of something: And no one knows what.

“It’s a precarious situation,” said Gerald Friedman, an economist at the University of Massachusetts Amherst. “We really don’t know where this is going.”

Tracking the spread of the disease is complicated enough. Predicting its impact on a regional economy that the Commerce Department estimates is worth $500 billion a year is even harder. Several economists have said they expect the coronavirus to dent growth of the US economy this spring and to increase the odds of a recession. But modeling the precise effect of a fast-moving pandemic on a specific place like Boston — that’s tricky.

“It’s hard to know the extent of the issues yet,” said Mark Melnik, director of economic and public policy research at the UMass Donahue Institute. “And things have accelerated really quickly.”

It’s clear the problems are growing.

Chris Coombs, a chef who owns four Boston restaurants, estimates the postponement of this weekend’s New England Seafood Expo alone will cost him at least $50,000 in sales, maybe $100,000. Those 18,000 fish-buyers are good customers, he said.

“They eat seafood all day,” he said. “And they visit the steakhouses at night.”

But now they’re not coming. Neither are the lunchtime crowds that typically fill Roxy’s Grilled Cheese in Central Square in Cambridge. Roxy’s and Whole Heart Provisions are in the lobby of a building occupied by the drug maker Takeda, which this week ordered most of its 5,000 local employees to work from home. Just on Monday, the restaurants’ sales were down 35 percent, said owner James DiSabatino. Then on Tuesday he got news that Harvard University, where he has a Whole Heart Provisions in the Smith Campus Center, was sending students home for the year.

Now DiSabatino is trying to determine if he’s going to have to lay off staff.

“It’s just guessing right now,” he said. “What we’re looking at is finding out, with 24 hours’ notice, that our business is going to decrease by 50 percent.”

At companies where most people can work remotely, the disruption is likely to be more manageable. Kendall Square, where several big tech and life-sciences companies were encouraging people to work from home, is notably quieter than usual. The lobby of the Kendall Marriott, normally a hive of networking meetings on a weekday morning, now holds just a few people pecking at laptops. The headquarters of Biogen, the drug maker whose conference last month became the epicenter of Boston’s outbreak, is dark, the blinds on its ground-floor windows closed, just one cleaning person visible in the lobby one morning this week.

At most Kendall Square companies, the work goes on, just in a different way, said C.A. Webb, president of the Kendall Square Association, which held its board meeting on Google Hangout for the first time this week.

“This may serve as a social experiment in how we do our science, and how we do meetings,” Webb said. “Rather than there being a lot of hand-wringing, or a sense of isolation, we’re seeing folks get pretty creative in how they use platforms.”

But, for people who have to be at work in person and whose incomes hinge on consumer spending — restaurant workers, for example, or tour guides — the risk of illness is compounded by worries about losing jobs.

Boston-area hotels are suffering already, with industry experts and trade groups saying bookings have fallen roughly by half. That means fewer shifts for workers like Elizabeth Cardoso, a housekeeping supervisor at a Back Bay hotel. She was supposed to work five days this week, she said, but there was enough work only for two.

“People are scared to travel, and I don’t blame them,” Cardoso said. “But it’s sad that we have to worry about how we’re going to pay the rent.”

Ssemambo, the Uber driver, is worried, too. He’s still driving, and wiping down his car seats every chance he gets, to keep both himself and his passengers safe. But he’s also watching the number of passengers dwindle. Business is down about 15 percent, he estimated, and that’s before all the college kids leave town.

“The community is nervous and scared,” he said. “Most of our customers are students and people who use the T, and they’re avoiding crowds. It’s limiting demand.”

Compounding the anxiety: No one has any idea how long this will last, or how bad it might get.

With coronavirus test kits in short supply, little is known about how extensively the virus has spread in Boston and the United States, and whether more-extreme measures to contain it — such as the nationwide quarantine imposed Monday in Italy — will be necessary here.

That uncertainty makes it harder for policy makers, companies, and everyday workers to think through how best to cope, said Gillian Mason, co-executive director of Massachusetts Jobs With Justice.

“It’s really hard to make decisions when you don’t know if this is going to be a short-term or long-term thing,” she said. “Are we talking about acute triage? Or is this a new normal?”

Either way, it can’t end soon enough for Bill Sykes.

He and his son run a company that erects fencing for 5K races, parades, and other public gatherings that are being called off left and right. This is usually a busy time of year, between St. Patrick’s Day and spring road races, but they’ve had five events cancel in the next two weekends. As a result, Sykes has had to lay off his three full-time staffers and has no work for his weekend part-timers. He’s anxiously awaiting word on whether the Boston Marathon — where he lines fencing from Cleveland Circle to Kenmore Square — will happen or not.

“We’d have 30 people working on the Marathon,” Sykes said. “That’s the big one for us.”

Many industries likely to be hit hardest in any prolonged period of self-quarantine — restaurants, retailers, museums, local theaters — are already struggling, squeezed between rising costs of rent and labor and an economy that has moved increasingly online.

Those are the sort of places people turn to for community in times like these, said Matt Chapuran, executive director of the Lyric Stage Co. in Boston. And he worries that coronavirus, if it keeps theatergoers home en masse, could prove to be the death knell for cultural institutions like his that already operate on thin margins.

“Nobody knows what’s going to happen,” he said. “All we know is that the longer we’re in this state of anxiety, the more damage it’s going to inflict on the fabric of our community.”

Shirley Leung of the Globe staff contributed to this report.