Why so many empty shelves at your local supermarket? It’s complicated.

Shelves that held meat products were partially empty at a grocery in Fairfax Va., on Thursday.OLIVIER DOULIERY/AFP via Getty Images

Grocery stores across the United States are seeing empty shelves that once held products ranging from bread to produce to meat, as a surge in COVID-19 cases due to the Omicron variant adds another layer of complication to a system already strained by supply chain issues and worker shortages.

While the sparser selection may be reminiscent of spring 2020, when toilet paper and cleaning supplies were hard to come by, there are additional issues at play this time around, industry organizations and experts said. Nearly two years into the pandemic, snags in the supply chain continue, but worker absences due to the broad reach of Omicron have played a significant role in the shortage of goods at stores.

“Omicron absenteeism is by far the biggest driving factor behind this,” said Katie Denis, vice president of research and industry narrative at the Consumer Brands Association. “If you don’t have the people to make the products, ship the products, deliver and stock the products, you’re going to be in a difficult situation with what shows up on store shelves.”

Grocery stores typically have about 7 to 10 percent of their items out of stock, Denis said. But now, it’s running at about 12 percent for all products. And, it’s even higher for food and drinks, about 15 percent — potentially double the amount of items that are typically unavailable.

“These are higher numbers than we have seen throughout most of the pandemic,” Denis said.

At Stop & Shop in Jamaica Plain on Friday, produce was well stocked. But there were limited choices of meats, such as pork and beef, and shortages of packaged goods including cooking oil, tortillas, and bottled water.

Tommy Tornburg, 50, a Jamaica Plain resident, said that he has recently had trouble finding packaged items, specifically frozen food.

“When COVID first kicked in about a year and a half ago, you couldn’t get toilet paper, things like that,” he said. “Now that’s there, but you can’t get a lot of food items and things like that, especially packaged.”

Stop & Shop said in a statement that its markets, like other grocery stores, are seeing product shortages as suppliers contend with labor and transportation challenges due to COVID.

“The Omicron variant, in tandem with recent weather disruptions, have exacerbated these gaps and the impact is felt across the grocery industry,” a spokeswoman said in an e-mail.

Jessica Dankert, vice president of supply chain for the Retail Industry Leaders Association, said the items that are unavailable seem to run the spectrum and are “constantly evolving.”

“You may go to a store one day and not be able to find product X, you go back in a day or two and it’s fully stocked,” Dankert said. “It’s kind of a moving target in terms of where you’re seeing the impacts.”

Grocery stores have adjusted to a baseline level of supply chain disruption throughout the pandemic. But the addition of winter storms, the holidays, and Omicron have added a layer of congestion, Dankert said. There’s also been a general increase in consumer demand for groceries of all kinds, as more people spend time at home due to the COVID surge.

Experts said every part of the supply chain is experiencing problems: shortages of materials needed to make the goods, the workers producing them, the transportation of the products to the stores, and the stocking of shelves within the stores. In October 2021, the American Trucking Association reported a shortage of more than 80,000 drivers, a “historic high” for the industry. The National Grocers Association noted a recent survey showed some stores operating with fewer than 50 percent of their usual workforce at some periods during the pandemic.

These supply issues have also driven up prices on many products. According to the Bureau of Labor Statistics’ consumer price index, grocery prices have risen 6.5 percent in the past year, compared to a 1.5 percent annual increase over the past 10 years.

Michael Klein, a professor of international economic affairs at Tufts University, noted that prices have risen more acutely for specific sectors, such as meats, poultry, fish, and eggs, which increased by 12.5 percent over the past year, according to the Bureau of Labor Statistics. The fact that meat prices have gone up more than other categories of grocery items tracks with the fact that jobs in the meat industry have been more difficult to fill.

“That lines up with the explanation that meat-packing places are unable to fill jobs, whereas there are not the same kind of labor supply issues for dairy,” Klein said.

At Star Market in Quincy on Friday, Brenda Lessard, 57, a former employee of the market, said she typically feeds her dog with chicken drumsticks. After seeing the price had increased to $7 for a pack of six, she opted not to buy them.

“I’m not eating as much. I’m not shopping like I used to,” Lessard said. “It’s really bad.”

Some in the industry had different takes on how long the shortages will endure. Dankert believes the issues are already beginning to dissipate, while Denis warned the next few weeks are going to be “difficult” until the Omicron surge is clearly in decline.

One way to help alleviate the problems would be increasing the availability of COVID tests in order to allow workers to return to work safely and faster, Denis said. The Biden administration’s pledge on Thursday of 500 million additional free, rapid COVID tests was welcome news, Denis said.

“If there’s one solution to this apart from waiting for the peak to hit and things to start to calm down, the faster that we can get people back safely to the workplace, the faster the supply chain can recover and consumers will see stocked shelves,” Denis said.