GARDINER — Anyone who had a ticket for Denny Breau’s performance Saturday at Johnson Hall Performing Arts Center had to make other plans.

The musician, booked to play a show at the historic opera house as part of its fall season, had to cancel at the last minute after being exposed to COVID-19.

“That’s the first time during this whole pandemic that’s happened,” Michael Miclon, Johnson Hall’s executive artistic director, said Friday.

Last-minute cancellations are only one of the hurdles that entertainment venues face as people across central Maine are resuming their normal lives more than a year and half after the global COVID-19 pandemic was declared.

Even as concert halls and opera houses open their doors to the public, it’s not clear that audiences are ready and willing to come back. And if they are, not all are willing to comply with public health restrictions requiring proof of vaccination or of a negative COVID-19 test.

At the same time, booking or rebooking acts has been hard as some performers have had trouble booking a tour itinerary that makes sense.

“We’re all just doing the best we can do with the information we have to make the best decisions and still do what we do,” said Michelle Sweet, executive director at the Waterville Opera House.

Going into the fall season, Miclon, Sweet and others responsible for putting on a season of shows were watching the reports from the state’s Center for Disease Control & Prevention to track the infection rate across Maine.

But they also had another piece of information to consider: at the end of August, the Maine State Music Theatre canceled its fall schedule at the Westbrook Performing Arts Center because of poor ticket sales and backlash over its requirement for ticket holders to show either proof of vaccination or a negative COVID-19 test.

At about the same time, the number of new COVID-19 cases reported across the state started to increase, reaching a peak at the end of September. Since then, the numbers have decreased, with both the seven-day and 14-day averages hovering around 500 cases for the last two weeks.

And while the number of people across Maine who are vaccinated against the disease has continued to grow, Miclon said it’s the vaccinated people who are being more careful about coming to shows.

“It’s so weird,” he said.

Trying to determine what audiences will do is key.

In the first half of 2020, the Maine Arts Commission conducted an Audience Outlook survey, designed to measure audience comfort and provide insight into opening performance spaces in Maine.

The summary of results showed that just over half the people surveyed would “not be comfortable” attending a show, regardless of the size of the hall. When asked how to make attending a live show safe, the top answer was after a vaccine or immunity.

This year, however, the Arts Commission opted not to conduct a survey.

Ryan Leighton, the commission’s marketing director, said the commission opted instead to see what performing arts venues had planned for the summer season. The majority had adopted safety protocols based on the data available at the time.

“As a state arts agency, we thought it was better to rely on the data sets and metrics that are backed by national studies rather than circulate another Maine survey,” Leighton said via email.

He noted that many Maine venues are mandating that audience members be vaccinated or show proof of a negative COVID-19 test.

For now, venues are pressing ahead, and the results have varied.

From a concert perspective, the crowd response depends on the artist and their draw.

In Waterville, concert-goers showed no hesitation at buying tickets for two recent shows, Blues Traveler and LeAnn Rimes, Sweet said, and both were sell-out shows for the 800-seat theater.

But Chris Thile, a Grammy winner and a MacArthur fellow, didn’t draw the ticket sales the opera house needed to meet the cost for putting on the show.

“The crowd is an older, more conservative MPBN kind of crowd, a different audience from Blues Traveler for sure,” she said. “That’s a show that typically would have been a great boost for us revenue-wise.”

But it was not.

Now, as the opera house prepares for the upcoming performance of “Clue,” Sweet said tickets are selling fantastically. She said she’s not sure whether it’s the name recognition for the show or whether people are just craving live in-person entertainment.

At the Snow Pond Center for the Arts in Sidney, so far, people are coming back.

“We have successfully had two concerts in the last month,” said Christa Johnson, director of development at Snow Pond.

On Monday, Livingston Taylor was the first artist to appear inside since the pandemic shut the venue down 18 months ago.

“When I did the introduction welcoming people to Snow Pond, I got a little emotional,” Johnson said. “All I could do was say, ‘thank you,’  because we require everyone to be vaccinated or show a negative test. Everyone worked with us, and we had a full house.”

Ordinarily, Snow Pond — which is home to the  New England Music Camp and the Maine Arts Academy — has a summer concert series in its amphitheater, and a winter series in its Alumni Hall. Alumni Hall  accommodates 300, but seats have been limited to 200 to give people the chance to spread out.

Shemekia Copeland, an electric blues singer, is scheduled to appear Dec. 9, and Johnson said ticket sales have been strong.

At the Augusta Civic Center, Sawyer Brown is scheduled to perform on Dec. 3, rescheduled from the spring of 2020. The show has been rescheduled several times since then, and it will be the first large-scale event the center has put on since the pandemic started.

“We’re at about 1,200 tickets now,” said Margaret Noel, director of the Augusta Civic Center. “What I am finding is that most people are waiting for the last minute to buy stuff because they don’t know if it will be canceled. If we get between 1,500 and 2,000, it will be a good crowd.”

Because of the changing schedule, Noel said, Confederate Railroad will appear with Sawyer Brown because BlackHawk couldn’t sign on.

At Johnson Hall, some shows like Maine Event Comedy have sold out, and for the most recent show the venue had to turn some people away. “That was kind of encouraging,” Miclon said.

During the pandemic, Johnson Hall livestreamed a number of shows to allow people to watch from home and this fall, it has worked with some performers to continue to offer that option.

Paula Cole, who is scheduled to appear Nov. 14, is one of the artists who has agreed to the hybrid setup, but Miclon said, ticket sales have been slow to the point where it’s not clear that Johnson Hall would make any money from that show.

“I feel like people are waiting for the last minute to make these decisions,” he said.