COVID-19 vaccines are making their way into the arms of U.S. meat and agriculture workers, but companies and union officials said progress needs to be faster after coronavirus outbreaks idled slaughterhouses and sickened thousands of workers.

Vaccinating food workers could help prevent further production disruptions that sent meat prices soaring in spring 2020 and forced retailers such as Kroger Co. to restrict customers' purchases of ground beef and other products.

Nationwide, 22,000 meatpacking workers have been infected or exposed to the virus, and 132 have died, according to the United Food and Commercial Workers (UFCW) International union.

A U.S. Centers for Disease Control and Prevention committee in December recommended front-line food and agriculture workers receive access to vaccines ahead of people aged 65 to 74 and younger Americans with high-risk medical conditions.

But many states prioritized older residents, who account for the majority of U.S. COVID-19 fatalities, and other essential workers such as teachers.

Companies are constrained by limited supplies and regulations in individual states and cannot purchase vaccines directly from drugmakers.

"Priorities have shifted in the past two months in a range of states, and that has lowered the priority status of our critical and essential employees," said Keira Lombardo, chief administrative officer for Virginia-based Smithfield Foods, the world's biggest pork processor.

South Dakota, where WH Group's Smithfield runs a massive pork plant in Sioux Falls, may not begin vaccinating food and agriculture workers until April, according to state plans. It will first give shots to teachers, funeral home workers and people under 65 with underlying health conditions.

More than a third of Smithfield's 3,700 employees in Sioux Falls had tested positive for the virus by mid-June 2020, according to the U.S. Department of Labor. BJ Motley, president of the local UFCW union, said workers are asking when they can be vaccinated, but the company has not provided information about scheduling shots.

"All we can do is keep pushing," he said.

Smithfield said it told employees the vaccine will be distributed at the Sioux Falls plant once supplies are available.

Kim Malsam-Rysdon, South Dakota's health secretary, said the state's vaccine plan was developed in accordance with CDC guidelines. Vaccine allocation from the federal government is the biggest challenge facing states, she said.

The U.S. Department of Agriculture told Reuters it is "again contacting governors in each state to encourage they prioritize food workers for vaccinations, as public health agencies have recommended."

The United States has been shipping millions of doses of vaccines to states each week, but demand so far has outpaced supplies. By the end of March, vaccine producers plan to ship tens of millions more shots. The supply will be further helped by Saturday's U.S. authorization of Johnson & Johnson's one-shot vaccine.

Julie Anna Potts, president of the trade group North American Meat Institute, said last week she would like the federal government to be more involved with getting vaccines to meatpacking workers.

"Unfortunately it's just been kind of a potluck at the state level," she said.

At Tyson Foods, the nation's largest meatpacker by sales, only 2,000 out of 100,000 hourly workers received vaccines as of Feb. 25.

JBS USA closed a beef plant in Greeley, Colo., on Friday for vaccinations. Cargill Inc. worked with health care providers to vaccinate employees at a beef plant in Kansas and at off-site locations in Nebraska and Michigan. At chicken processor Perdue Farms, about 800 employees out of 21,000 had received one shot by Thursday.