The doctors and nurses of South Seven gathered quietly for daily rounds, dispensing with jokes and chitchat in anticipation of a discouraging review of 12 critically ill patients — 11 with COVID-19.

"766?" asked the charge nurse about a man in that room.

"Ravaged from the complications of COVID," his doctor replied.

768? "He was rallying and then the wheels came off," another reported.

772? "He had a rough day yesterday."

The merits of COVID-19 vaccination might seem opaque outside the hospital walls, especially given an increase in breakthrough infections among fully vaccinated Minnesotans, but they are alarmingly transparent to the caregivers in this ICU at North Memorial Health Hospital in Robbinsdale. Ten of the COVID-19 patients, ranging from 35 to 85 years old, were unvaccinated.

North opened the doors Wednesday to South Seven to show how the unvaccinated are suffering the worst cases and contributing to a historic level of pressure on hospitals. Minnesota reported a 2021 record of 1,678 COVID-19 hospitalizations on Thursday, and that COVID and non-COVID patients combined to leave only 18 of 1,012 staffed adult ICU beds open.

North Memorial's chief executive, Dr. Kevin Croston, made a social media appeal Wednesday for people to get vaccinated and take precautions this holiday season.

Minnesota is close to "experiencing scenarios that we've never had to experience before" in terms of rationing or delaying care, he said. "Honestly, if you could come and see what I see on a daily basis, I think it would inspire you to behave differently."

The quiet mood grew quieter during rounds on South Seven until nurse practitioner Elizabeth Hutter reported on a woman in 773. Her breathing had stabilized only two days after a respiratory arrest. She was the only vaccinated COVID-19 patient.

Amid "wows" and cheers, Dr. Kristen Hasson smiled and wished she could have given the team positive news like her colleague. "She gets the wins!" she said.

Hospitals didn't expect this many losses 21 months into the pandemic, not after a summer in which vaccinations were on the rise and many ICUs had no COVID-19 cases for days. However, a highly infectious delta variant emerged and seized on the vulnerabilities in Minnesota, where more than 1 million people remain unvaccinated.

"This go-around, the mortality is incredibly high," said Hasson, a critical care specialist. "The big concern of our team is we're doing all of these efforts and we're not seeing a lot of people walk out of our ICU anymore."

Breakthrough infections in fully vaccinated Minnesotans have become a larger share of the state's pandemic wave this fall, prompting recommendations for booster doses because of waning immunity from initial shots months ago. Vaccinated people made up little more than 20% of coronavirus infections and COVID-19 hospitalizations at the beginning of the latest wave in July. By the last week of October, they made up 44% of infections and 33% of hospitalizations.

The proportion of sickest cases needing intensive care hasn't budged in that time — and not just at North Memorial. Collectively on Tuesday, the Allina and Sanford hospital systems reported 124 COVID-19 patients in intensive care and 114 (or 92%) were unvaccinated.

Nine unvaccinated COVID-19 patients filled all nine staffed ICU beds on Friday at St. Joseph's Medical Center in Brainerd. Three patients needing intensive care were receiving it instead in the emergency department. Dr. Greg Davis, the ICU director, recalled a cardiac arrest during an emergency procedure last week and a response team rushing in to save the COVID-19 patient.

"You know what's easier than this?" he said, looking up at the relieved team after the patient was stabilized. "Getting two shots."

The median age of COVID-19 patients who died in intensive care over the past seven months was 82 for those who were vaccinated and 69 for those who were unvaccinated. While this partly reflects a higher vaccination rate among the elderly, state Health Commissioner Jan Malcolm said it also accentuates the risks.

"The difference between the vaccinated and unvaccinated populations remain very, very stark," she said. "The danger for unvaccinated people has probably never been as high as it is right now with this degree of viral transmission around the state."

Hospitals had more COVID-19 patients at one point last year — with a record 1,864 on Nov. 29, 2020 — but they haven't been under this amount of sustained pressure before. Total ICU usage has averaged more than 1,200 patients throughout December. That happened only sporadically earlier in the pandemic.

Terry Reynolds of Plymouth has seen the impact on almost a daily basis since his wife, Carolyn, was declared no longer infectious and he was allowed to visit her on South Seven. On Wednesday, he bowed his head at her bedside and prayed after three weeks of intensive care that she would recover from COVID-19. He prayed too for all the patients on the floor. But the experience hasn't changed his mind on vaccination. Safety concerns and vaccinated friends who got COVID-19 have left him with no confidence in the shots.

"I know people have a hard time with people who don't get vaccinated," said Reynolds, 66, a retired IT analyst for North Memorial, "but I just don't want it."

Reynolds talks to his wife and plays music she likes while the 69-year-old is on a ventilator. Their last back-and-forth communication was on Nov. 28, when her oxygen depletion was so bad that she couldn't text cohesive words.

"I can't can't vet .uoxye up so Mo no food fprme," she texted.

Reynolds figured she was saying her oxygen level was too low to swallow food.

"OK, just keep getting better," he replied. "I love you!"

For the caregivers on the floor, it isn't hard to provide care and compassion for unvaccinated patients and family members, but it is frustrating to encounter so many severe illnesses that might have been avoided.

After five years on South Seven, critical care nurse Katie Knapp said she is emotionally drained and thinking about another job. She looked down the hall at one room and remembered withdrawing life support on a COVID-19 patient with grieving family present two weeks ago. Her last three patients in that room died of COVID-19.

Knapp isn't prone to superstition, though. "Something bad has happened in every room," she said. "And good stuff, too."

Knapp allowed herself in the summer to believe the worst of COVID-19 was over, so the current surge has weighed on her.

"I remember when the very first case came back [this summer] and it was like, 'Oh, it's just a blip, just a little breakthrough blip,'" she recalled. "Then there was another one and another one. This was supposed to be a blip."