The spike in coronavirus infections has some Philadelphia restaurant and cafe owners again wrestling with the decision to close — a move that would idle workers counting on holiday paychecks and disappoint customers, as well as affect the businesses’ bottom line.

So far, only a fraction of restaurants in the region have closed after staffers test positive, mostly smaller establishments already stretched thin by personnel shortages.

The popular Wm. Mulherin’s Sons and Hiroki, side by side in Fishtown, announced Monday that it had closed for a few days after staffers were infected, ownership acknowledged. The restaurants join Khyber Pass Pub in Old City, Middle Child Clubhouse in Fishtown, and Fitz & Starts in Queen Village, among those that chose to pause over the weekend. Fishtown Social, a bar and bottle shop, closed its bar and will sell bottles of wine for the foreseeable future. Juana Tamale, a new shop in South Philadelphia, has opted to open for takeout only.

The restaurant-reservation app Resy said Monday that it had seen a steady uptick in cancellations in Philadelphia — at a rate 5% to 10% higher when compared with average cancellation rates from October and November. The cancellations include restaurants that shut down and cleared the reservations from their books.

Other restaurateurs, meanwhile, said they did not notice customers staying away last weekend as word began spreading about the omicron variant. The city has recommended avoiding large gatherings over the holidays.

Matt Cahn, who owns Middle Child Clubhouse, said he would keep the Fishtown bar-restaurant closed through Dec. 28 not because of new cases, “but just because everyone wants to see their family this week and feel safe about it.” Working in a restaurant, he said, “is literally being a sitting duck all things considered when other people work from home.”

There is no blueprint or standard practice guiding closures right now. Restaurateurs interviewed for this article said they act quickly when informed of an infected employee and shut down as the last resort — much as they did before vaccines were widely available and standards began to relax.

“The tough thing for me is that being honest about having a positive case makes us look bad and irresponsible,” Cahn said. Many restaurants have positive cases and are not shutting down out of fear of losing business.

Others are announcing on social media that they are temporarily closed, but are not disclosing the reason.

Jon Myerow, an owner of the Tria Cafes and Bar Poulet in Center City, is trying to be transparent. He said his affected staffers are asked to quarantine and are then retested, especially if the first test was a rapid test. The entire staff is then tested by a private health-care provider. Before vaccines, he said, they would close a restaurant with just one positive case. They are working on new protocols, but he said, “our guiding principle is to err on the side of safety. Our protocols will continue to change as we all learn more about omicron.”

Many restaurants are insisting on proof of vaccinations for employees and patrons, ahead of new rules that take effect Jan. 3. Teddy Sourias, who employs 330 people across a half dozen bars and restaurants including Uptown Beer Garden and Tradesman’s, said he would direct his employees to return to wearing masks — which they began doffing when proof of vaccination for entry became restaurant policy.

Meanwhile, through a grant provided by the William Penn Foundation, the Pennsylania Restaurant & Lodging Association has partnered with Jefferson Health and the Chamber of Commerce for Greater Philadelphia to provide access to COVID-19 testing for Philadelphia restaurants and hotels and their employees. Through this program, PRLA will reimburse employees up to $60 for a COVID-19 test.

The pandemic has been particularly cruel to small corner bars because of their status as gathering spaces with comparatively little takeout-food business. Patti Brett is demanding the proof of vaccinations — and is strictly enforcing mask-wearing — since reopening Doobies Bar at 22nd and Lombard Streets a week ago after it was closed indoors for most of 2020 and 2021. On Tuesday, she announced that she would close till at least Dec. 29 out of safety concerns.

Her lifeline throughout the pandemic was the Pennsylvania legislature’s temporary approval of cocktails to go, but that authorization expired last summer. “I think we’ll be OK,” Brett said. “At least I’m hoping.”