At the start of another busy day giving COVID-19 shots, Freeman Mjolsness laced his fingers while quietly describing why he's working again at age 83.

Back when the vaccines were being introduced late last year, Mjolsness was on the receiving end of countless emails seeking people who could serve as vaccinators in the enormous campaign to control the pandemic. Still active and in good health, he figured: Why not?

"I just have this ingrained concern about the health of the public," Mjolsness said, before setting off to vaccinate patients at a CVS Health store in Plymouth. "You just know that they need help."

Pharmacies have provided more than 2.6 million doses of COVID-19 vaccine in Minnesota as of late November, just over one-third of the statewide tally of 7.7 million. They've been the single largest group of vaccine providers, just ahead of primary care, according to data from the Minnesota Department of Health.

To get the job done, drug stores ramped up hiring. In a few cases, retirees have contacted the state pharmacy board to learn how they can renew licenses in order to help, said Cody Wiberg,executive director of the Minnesota Board of Pharmacy.

Mjolsness has done his part. Working up to four days per week over the past few months, he estimates he's administered at least 1,200 doses at the retail pharmacy. Earlier this year, he also was part of a drive coordinated by the federal government that saw CVS Health and other companies immunize residents at long-term care facilities across Minnesota.

"I'm sure I'm over 2,000," Mjolsness said.

There aren't hard numbers yet, but it's likely pharmacists in the state this year will have administered the most vaccines in a 12-month period, Wiberg said, since the early 2000s when they first started giving shots in Minnesota.

Retired pharmacists giving shots is a variation on a theme that stems from the early days of the pandemic, when some retired doctors in Minnesota prepared to help with an expected surge of COVID-19 patients. Mjolsness said he doesn't dwell on the historical nature of these encore performances.

"Let's hope it doesn't happen again," he said. "Lord knows, this itself could go on and on. Until we get to 100% involved, it's still going to mutate and keep involving some people."

Growing up in rural North Dakota, Freeman Mjolsness first considered a career in pharmacy during trips with family to a nearby town. The drug store included a soda fountain, so Mjolsness sipped a malt while watching the pharmacist do his work.

"I thought: 'Gee, that beats the heck out of cutting hair or farming.' "

His father was a barber and his mother was a beautician. The family moved to Fargo so Mjolsness could experience a larger high school before going off to college, where he studied pharmacy.

When he graduated from North Dakota State University in 1959, it was a different time. Pharmacists didn't do immunizations, and patients tended to accept recommendations about whether to get them. Recalling support for the polio vaccine during the 1950s, Mjolsness said that "people at that time went along with what they were told. ... Nowadays, everything seems so political."

In the 1960s, he became the pharmacist at a drug store in Bismarck, a job he held for more than three decades.

Much like his parents, who sometimes would drive around the countryside cutting hair, Mjolsness on occasion took prescriptions to patients who couldn't make the trip into town. It wasn't a delivery service, he said, so much as a response to circumstances — like the time Mjolsness, his wife and their two daughters drove 50 miles to deliver medicine to a patient who'd been hurt in a car wreck.

"We dropped it off," he recalled, "and had a little evening drive at the same time."

After retiring in 1996, Mjolsness and his wife moved to the Twin Cities to be closer to grandchildren. A few years later, he decided to get back into pharmacy work on a part-time basis, but had retired a second time when the pandemic hit.

Once vaccines started to become available, Mjolsness reached out to CVS Health, where he previously worked. The Rhode Island-based pharmacy giant was in the midst of hiring 10,000 pharmacy technicians and workers to meet the need for immunizations.

"When he heard his previous employer was administering vaccines to nursing home residents last winter, a community hit especially hard by the pandemic, Freeman brushed off his white coat, renewed his pharmacy license and rejoined the company," CVS Health said in a statement.

With about 59% of the U.S. population fully vaccinated against COVID-19, the ongoing campaign looks to be the nation's largest ever vaccination push, said René Najera, editor of the History of Vaccines Project at the College of Physicians of Philadelphia. The next closest campaign in scale, Najera said, was the polio vaccination drive that started in 1955. By 1957, half of U.S. residents younger than 40 were vaccinated.

As with COVID-19, the drive to vaccinate against polio "recruited people from all walks of life to get it done," Najera wrote in an e-mail.

Mjolsness sounds steady and matter-of-fact when describing why he's back at work after all these years. To family members, it shows what they've found remarkable about him all along.

"He's got to keep active. He seems very introverted and he's kind of quiet, but he needs that social interaction — he loves it," said Julie Lindstrom, his daughter. "He's got a heart of service and he wants to help people."

The CVS store where Mjolsness works doesn't have a soda fountain like the pharmacy of his childhood — nor does it have a coffee bar, he notes wryly, that could come in handy during long shifts. Coming out of retirement, he's had to acclimate himself once again to packing a lunch that sustains him through an eight-hour day.

At this point, it looks like those workdays will continue for a while considering the resurgent demand for vaccine in Minnesota. As of Tuesday, vaccinators across the state had administered more than 695,000 doses in November, the highest monthly total since May.

"We're turning people away every day that want to get included," Mjolsness said, "but we're already booked."