Concerns related to the spread of the new coronavirus have organizations canceling conferences and major events across the country, including here in Philadelphia, which has one of the nation’s most robust convention circuits, leaving tourism officials, hotels and workers scrambling to manage the fallout of losing thousands of visitors and tens of millions of dollars in local economic impact.

At least two major conferences in Philadelphia expected to draw a combined 21,000 people to the city have been canceled, as have several smaller meetings. Other organizers planning summits and professional gatherings say they are closely monitoring the situation and urging attendees to avoid physical contact.

Business conferences and conventions are a major economic driver in Philadelphia, which is a top destination for such gatherings. The industry pads revenues at hotels, restaurants, and tourist destinations across the city, particularly in the beginning of the year when tourism for leisure’s sake is at its lowest. Loss of that revenue could threaten the livelihoods of more than 70,000 hospitality workers in the city.

Kavin Schieferdecker, a senior vice president at the Philadelphia Convention and Visitors Bureau, said the group, in charge of sales and marketing for the city’s major conferences, is concerned about how canceled events will affect the local economy and the workers who power it. The conference business accounted for a third of hotel room stays in Center City in 2018, the bureau estimated.

“When these events cancel, that causes people to have to readjust their lives in some way,” he said. “That’s heartbreaking for us.”

And Ed Grose, executive director of the Greater Philadelphia Hotel Association, said its member hotels have seen “a lot” of cancellations in the last week and they "suspect it will get worse before it gets better, so we must do everything we can to let visitors know that Philadelphia is open for business.”

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Although there have been no cases in Philadelphia, a handful of “presumptive positive” cases of COVID-19, the flulike disease caused by the new coronavirus, have been confirmed in counties that border the city, including Delaware and Montgomery in Pennsylvania and Camden County in New Jersey.

Health officials in Philadelphia have not called for widespread “social distancing" — the concept of canceling public gatherings and restricting travel — which experts say can slow and delay the spread of new infectious diseases. Some industry leaders in the convention and meeting-planning space are urging organizers to continue participation in big events, as there are no federal restrictions on travel within the United States.

But that hasn’t stopped some trade groups, which have watched as officials have linked cases of coronavirus spreading to conferences and conventions, including 15 cases tied to the same Boston biotech company conference, from canceling. The annual South by Southwest, a music festival and conference held in Austin, Texas, was canceled. And this week, a handful of lawmakers self-quarantined after a person tested positive for coronavirus after attending a conservative conference.

On Monday, the American Chemical Society for the first time in more than 100 years canceled its annual meeting, which was to take place at the Pennsylvania Convention Center and was expected to draw 15,000 visitors to Philadelphia the week of March 22. The Convention and Visitors Bureau estimated that, in 2016, the last time the group held its national meeting in Philly, its regional economic impact was upward of $30 million.

Glenn Ruskin, ACS vice president of communications, said more than a thousand attendees had already canceled and a thousand abstracts out of 12,000 were withdrawn. He said the group’s leadership decided Monday to cancel the event after watching the exponential growth of confirmed cases.

Ruskin said ACS was concerned that bringing in membership from around the world could expose both attendees and Philadelphia residents to the virus.

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And on Sunday, the American Academy of Allergy, Asthma & Immunology (AAAAI) announced it canceled its annual meeting, which was scheduled to be held at the Pennsylvania Convention Center beginning Friday and was one of the city’s largest conferences of the year, drawing 6,500 people. The group said its leadership felt precautions to keep attendees and exhibitors safe “would not be enough."

David Lang, president of the AAAAI, said the group was both concerned for the safety of members and was also hearing from speakers and attendees dealing with travel restrictions imposed by their workplaces. Lang himself, who works at the Cleveland Clinic Lerner College of Medicine with 17 other allergists, was told by higher-ups he was the only one allowed to attend the annual meeting.

AAAAI, considered among the most preeminent medical associations in America, has never canceled its annual meeting in its 77-year history.

“On balance, I believe we made the right decision,” Lang said, noting that he wrestled with the impact the cancellation would have on the local economy in Philadelphia, “and the only one we could under the circumstances.”

John McNichol, president and CEO of the Pennsylvania Convention Center, said the leadership team is working with public officials, advising organizations that have upcoming meetings and projecting that it’s open for business.

What keeps him up at night is the impact on the industry and its workers.

“The 75,000 men and women who work in the hospitality industry, their livelihoods are arguably in jeopardy,” he said. “The more people decide for whatever reason [to cancel events], there is a trickle-down impact that really will hurt the line workers.”

Dermot Delude-Dix, a research analyst with Unite Here Local 274, which represents about 4,000 hotel, airport and food service workers, said some of the union’s members have already seen “massive” reductions in hours.

“This is going to hit these companies’ bottom lines,” he said, “and our concern is that we do everything we can to protect our members still having to pay the rent, still having to pay bills, still needing health insurance.”

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In addition to the events at the Convention Center, other smaller gatherings are being axed, including a pediatric research conference scheduled to take place starting Friday at the Hilton Philadelphia Penn’s Landing and a neuropsychiatric trade association meeting next week at the Westin Philadelphia.

On Monday, an association of college business officers canceled a conference scheduled for Wednesday at the Loews Philadelphia Hotel, and in New Jersey, Cooper’s Ferry Partnership postponed its annual meeting, scheduled for Wednesday at BB&T Pavilion in Camden.

Also, students at the University of Pennsylvania canceled the 2020 Penn Wharton China Summit, which aims to strengthen U.S.-China relations and was expected to draw more than 1,500 people to the school next month, including such keynote speakers as Forbes Media CEO Steve Forbes.

Meanwhile, some organizations hosting conferences in Philadelphia in the coming months say their events will go on, instituting policies to reduce and eliminate physical contact.

For example, a higher education group holding a conference in Philadelphia is asking attendees to stand three feet away from others, adopt a “no-handshake policy,” and use apps or AirDrop to trade contact information instead of exchanging business cards.

One of the largest conferences scheduled to take place in Philadelphia this year is hosted by the American Psychiatric Association. Its annual meeting, scheduled for late April at the Pennsylvania Convention Center, could draw about 20,000 people, according to estimates from the Convention and Visitors Bureau, and is still on.

The group says it’s in communication with both public health officials in Philadelphia and the CEOs of other medical organizations hosting similar conferences as the situation evolves.