U.S. companies responded to the new Covid-19 variant with a mix of both concern and confusion. Some executives scheduled calls with internal teams to assess the threat or peppered health advisers with questions, while many cautioned that they would hold off in making changes to operations until more is known.

The fast-spreading Omicron variant pushed companies in a range of industries to consider how safety measures and new workflows created during the peak of the pandemic could be reinstated. It also served as a reminder,...

U.S. companies responded to the new Covid-19 variant with a mix of both concern and confusion. Some executives scheduled calls with internal teams to assess the threat or peppered health advisers with questions, while many cautioned that they would hold off in making changes to operations until more is known.

The fast-spreading Omicron variant pushed companies in a range of industries to consider how safety measures and new workflows created during the peak of the pandemic could be reinstated. It also served as a reminder, executives say, that navigating through the unknowns of Covid-19 is a new reality of corporate management.

After the initial pandemic wave, and the Delta variant this summer, many companies grew accustomed to shifting processes quickly. That is giving executives comfort that they can adapt again, if needed, even as some worry whether the variant may be more transmissible than other strains of the virus or if it can evade some protections from vaccines.

“It’s important to not catastrophize and not to kind of just jump to the worst, but you’ve got to take it as a real threat,” said Brian Fielkow, chief executive of Jetco Delivery, a Houston trucking and logistics company. “It’s a risk, and how severe is the risk? We don’t know.”

Jetco Delivery CEO Brian Fielkow said it is important to take the new Covid-19 variant as a real threat but not to assume the worst.

Photo: Todd Spoth for The Wall Street Journal

Mr. Fielkow said he would watch for guidance from U.S. health authorities, and he planned to discuss the variant with a small team internally later this week.

With information still limited, though, Mr. Fielkow and other executives said they also want to be careful not to make rash decisions. At the marketing-and-sales software company HubSpot Inc., a pandemic-response team plans to learn more about the variant and then will discuss it this week, said Katie Burke, the company’s chief people officer.

HubSpot chose not to send an all-company message about the variant Friday, hoping to avoid worrying employees or interrupting those on vacation after the Thanksgiving holiday. The company also wants time to consider how the variant could affect company travel or in-person events. Managing through a pandemic that has stretched nearly two years means that companies must be careful in how they handle new issues, Ms. Burke said.

“We need to stay vigilant, and that means it’s more important than ever that not everything be an immediate reaction, a panic situation, all the above,” she said. “You’ve kind of got to save and conserve your energy and be thoughtful.”

Food retailers say they are waiting for more clarity around the new variant before making changes to their current operations. Safety protocols, such as mask-wearing and sanitizing, have been helpful in protecting employees and customers during the pandemic, they say.

Staffers at Pennsylvania-based Giant Eagle Inc. have reviewed materials released by the World Health Organization and are in contact with local health officials, said Vic Vercammen, chief pandemic officer at the chain of more than 400 supermarkets. His team has discussed the reports and potential risks, including the likelihood that the variant will arrive in the U.S.

“We are trying to determine, ‘Is this a variant that would be uniquely hazardous to the fully vaccinated?’ ” Mr. Vercammen said, adding that he expects to have clarity as more data comes in.

Until then, the company will continue with its sanitizing practices and applying safety protocols such as plexiglass guards and masks in stores; corporate employees will continue working in hybrid models. Giant Eagle, which expanded warehouse capacity earlier in the pandemic, has enough additional supply of shelf-stable items on hand to cover changes in demand, he added.

Some retailers say they expect consumers will want more cleaning products for their homes, though it remains too early to tell how the variant will affect shopper demand. “We are at the mercy of the information that’s provided for us,” said Michael Needler Jr., chief executive officer of Fresh Encounter Inc. based in Findlay, Ohio.

For the moment, many executives have questions. Over the weekend, Roslyn Stone, CEO of Zero Hour Health, a health-advisory firm, watched as her email lit up with inquiries about the new variant from restaurant and hospitality industry CEOs and other corporate leaders.

Some executives asked: “Is this real? What do you think? Are you panicked?” Ms. Stone said.

She replied that she was more concerned Saturday, after the U.K. reported its first cases and other developments emerged, but she reassured clients that it was early and said it could take weeks until more is known about vaccine effectiveness.

The emergence of the variant comes as many companies with more than 100 employees in the U.S. also wonder if they will need to comply with the Biden administration’s vaccination or testing mandate, which remains in legal limbo but had been set to take full effect in January.

Ms. Stone said one client wondered this weekend what to say now to unvaccinated workers, asking, “If we don’t know if the vaccine works through this variant, what do I tell my employees who I’m trying to encourage to go get vaccinated?” Ms. Stone recalled. “It’s a really difficult question.”

Keeping employees informed is another challenge. Guy T. Williams, chief executive of Gulf Coast Bank & Trust Co., a regional bank in Louisiana, plans to devote part of a staff meeting at 8 a.m. on Monday to discuss the new variant. Mr. Williams has used the all-employee calls throughout the pandemic to tell workers what the company knows, and doesn’t know, about the virus, and to update staffers on any changes to company operations. One message he expects to deliver Monday: Much remains unknown about the Omicron variant.

“It’s really too early to tell,” he said. “This could easily be overhyped, so until we get real medical intel, we’re not going to go to the barricades and think it’s a disaster.”

The company has already adapted to the pandemic, upgrading ventilation systems at bank sites and accelerating efforts to move more of its services online for customers, Mr. Williams said, which could make any new disruptions potentially easier to bear. Many corporate employees also continue to do their jobs at home. Should the bank need to return to drive-up only operations at branches, as it did early in the pandemic, it could do so, Mr. Williams said.

Keith Milligan, controller of Piggly Wiggly stores in Alabama and Georgia, read the news about the new Omicron variant on Friday after hauling holiday items like cranberry sauce and collard greens from one supermarket to another on Thanksgiving.

Mr. Milligan said he isn’t planning to operate his grocery chain differently because the facts about the variant—including how infectious or vaccine-resistant it is—remain unclear. He added that many supermarkets still have safety protocols in place, such as wearing masks.

“There’s one thing for certain about this pandemic. You may think you know how to predict things, but you can get surprised at any time,” he said.

Write to Chip Cutter at chip.cutter@wsj.com and Jaewon Kang at jaewon.kang@wsj.com