Meatpacker JBS USA has said that more than 20% of its employees have received a COVID-19 vaccine, while rival Tyson Foods Inc said more than 10% of its workers have received a shot.
Labour unions and meat companies have been pushing states to accelerate the vaccine rollout in the food sector to protect workers and avoid supply-chain disruptions from COVID-19 outbreaks, such as closures of slaughterhouses last year.
Companies are constrained by limited supplies and regulations in individual states and cannot purchase vaccines directly from drugmakers.
"While we are making good progress, there is much work left to be done," JBS USA chief executive officer Andre Nogueira said.
JBS said 14,000 US employees out of more than 60,000 have received vaccines and another 7,000 are scheduled for shots this week in states including Illinois, Texas, Nebraska and Minnesota.
Tyson Foods said 15,000 US employees were vaccinated in the past two weeks out of a workforce totalling 139,000.
The company is expanding onsite vaccinations to all its 24,000 employees in Arkansas and will hold 19 vaccination events in the state through 2 April, according to a statement.
More than 1,200 employees were vaccinated on 9-10 March at two Tyson facilities in Arkansas, the company said. More vaccination events are planned in California, Illinois, Missouri and Oklahoma, according to Tyson.
Last month, Tyson Foods Inc reported lower-than-expected first-quarter sales amid weak meat demand at restaurants during the pandemic. It expects demand to improve as COVID-19 vaccinations prompt people to eat out more often.