It feels almost like another lifetime when crowds of enthusiasts filed into the Pennsylvania Convention Center for events about new cars and Mediterranean-inspired floral exhibits.

Since those wintry days of 2020, cancellations of large meetings and conventions have piled up amid the pandemic. The city has lost out on at least 380 potential gatherings that would have brought 420,000 attendees to the city, according to the Philadelphia Convention and Visitors Bureau.

Tourism officials are predicting that it will take three to five years to return to 2019 levels of convention business, when the visitors bureau booked business for 585 groups that brought 788,000 people to the city.

Cue the doctors.

In an effort to get ahead of other cities that will be competing to host future meetings, the visitors bureau announced this month a new advisory group — PHL Health Advisors — to help businesses address questions about meeting and traveling safely.

“The competition for this business on a national scale will be incredibly fierce,” said spokesperson Alethia Calbeck. The organization believes that by drawing on the city’s medical community, and on its own advisory members, “we’ll be able to compete and win back this critical element of Philadelphia’s tourism business,” she said.

David Nash, founding dean emeritus of Jefferson College of Population Health, is serving as chief health advisor to the committee comprised of doctors, biotech executives, academics, and health executives.

“This is really important to the local economy,” Nash said. “When it’s safe,” he added, “we want to be like the first kid on the block to say, ‘Come here.’ This is not like a switch that you’re going to flip. This is going to take time, and people and resources.”

Nash spoke with The Inquirer after the 19-member subcommittee met by video conference Monday morning.

How would you explain this new role you have with PHLCVB?

“I’m going to be a translator, a synthesizer, a disseminator, a person who is going to help translate the science for the broadest possible audience,” Nash said. He views the job as supporting the visitors bureau to give prospective visitors “the best available information in a timely way, without politics, and to reinforce the message about washing your hands, social distance and wear a mask.”

Masks, he said more than once, are critical. “If 60% of people wore a 60%-effective mask, we’d crush it. It’d be over. The next best thing to a vaccine is wearing a mask.” (Nash has two types of masks: a “regular old surgical mask” available at drugstores, and cloth N95s, which he recommends that people practice wearing to get used to them. He also uses a bandanna when he goes running.)

What are some of the issues you covered this morning?

“Understanding what are customers asking,” Nash said. “It’s fascinating. Like any place, they want to know: Are the hotels adhering to the best possible guidelines? What’s it like getting back and forth to the airport? The convention center itself, which we’re lucky to have... is it up to speed?”

Are there other questions you’re anticipating from businesses?

“I’m anticipating more questions about testing,” Nash said. “Whom do we test? What time? Should we test them before they get on an airplane? When they get here? Do you have the overnight test? We haven’t gotten into that yet.”

He also expects to field more questions about hotel cleanliness, and about arrangements inside the convention center: “Can we have our meeting in this part? Who else will be there? How are we going to be separated? Is there enough distance to have, let’s say, 200 people in a room?”

Some of the answers will depend on input from the city, and what officials allow at the time. “We’re going to have to work closely, and it’s great that the advisory group has someone representing [state health department secretary] Dr. Rachel Levine and [Philadelphia health commissioner] Dr. Tom Farley.” Other members include Meghna Patel, the state’s deputy secretary for health innovation; Barbara Wadsworth, senior vice president of patient services at Main Line Health; and Jonathan Epstein, chief scientific officer at Penn’s Perelman School of Medicine.

Are there emerging answers to those questions yet, such as how soon do you get tested before you get on a plane?

“The short answer is no,” Nash said, adding: “Let’s put it this way, every big company is struggling with a plan to safely get people back to work. And so we have to learn from all these other employers, who, after all, might be exhibitors and want to have a meeting here.”

There will be “crossover” lessons, he said, between how employees return to a workplace, and how businesses would send their employees to an out-of-town business gathering.

“There’s no national strategy, so the private sector has to jump in here,” said Nash. “We just don’t have national leadership of any kind as it relates to school reopening, companies reopening...we’ve got to fill that gap.”

Has the advisory group discussed a timeline?

Big meetings are typically planned three to five years in advance, Nash noted. “That’s the time horizon,” he said. “I think we’re all hoping that in 2021, we could have some successful, safe, pretty large in-person [business] meetings in Philadelphia. That would be great. I’m hoping for that. But I think, realistically, it’s a three- to five-year time frame.”

The development of an effective vaccine will be one component of a return to normalcy. Beyond that, Nash said, “In some respects, it’s up to us. Wear a mask. Darn. It’s not that complicated.”