Four months into the COVID-19 vaccination campaign, the number of Minnesotans dying of the virus each day is down significantly from the peak in December.

It’s a sign the vaccines are working — particularly to protect the most vulnerable, who were vaccinated first.

But the state isn’t there yet. In recent weeks, Minnesota has seen an uptick in its COVID-19 hospitalization rate, from about 4 per week per 100,000 residents in early March to 14.3 per week per 100,000 residents mid-April.

It’s not just that hospitalizations are increasing that concerns public health officials. It’s also who the patients are: since the virus’ peak in the fall, the median age of people hospitalized has dropped by more than a decade, according to Minnesota Department of Health data. Doctors say the typical patient earlier in the pandemic was older, with multiple underlying medical conditions. Now, they still tend to have medical comorbidities, but they’re younger.

“We are definitely seeing younger patients than the first time around,” said Dr. Daniel Hoody, Interim Chief Medical Officer at Hennepin Health Care.

And while the current wave of COVID-19 cases has, on average, put younger people in the hospital, the share of people hospitalized with COVID-19 has increased for every age group except children. This suggests a more virulent, and likely more dangerous strain of the coronavirus that causes COVID-19 is circulating in Minnesota.

Younger people in the hospital

Between November and December, during Minnesota’s second wave of COVID-19, 11,627 people were hospitalized with COVID-19. Nearly half of patients were age 70 or older, and the trend was simple: the older the age group, the bigger share it made up of COVID-19 hospitalizations.

But something happened between that wave of COVID-19 late last year and the wave Minnesota is in now: vaccination. The first Minnesota residents to be vaccinated — people who live and work in long-term care and health care workers — got their shots in the final weeks of December. Since then, more than 40 percent of Minnesotans have been vaccinated.

Despite all the vaccinations, cases have begun to rise again. But with so many of the state’s oldest, most vulnerable vaccinated, there hasn’t been a corresponding rise in deaths.

Since vaccines have made older residents less vulnerable to the disease, though, the average age of those hospitalized has been getting younger. In March and early April, people in the 50 to 59 and 60 to 69 age group were the most represented in hospital beds. Absent specific underlying conditions, these groups have only recently been made eligible for vaccination in Minnesota. Regardless of age, people of color are disproportionately represented among the hospitalized.

“I think the average patient that we’re seeing now is probably 55 years old, unvaccinated and has some of the risk factors that we’ve seen throughout the epidemic,” said Dr. Mark Sannes, an infectious disease specialist at HealthPartners.

Hospitalization rates rising

Vaccines are helping reduce the number of Minnesotans that get sick with COVID-19. But in the latest wave of COVID-19, for those who do get sick, the share that end up in the hospital is higher for all adults.

Between November and December, 2.1 percent of Minnesotans age 40 to 49 who tested positive for COVID-19 were hospitalized. Between March and mid-April, that rate was up slightly to 3.3 percent; the share of Minnesotans age 50 to 59 who were hospitalized went from 3.7  percent to 6.1 percent, and the share of Minnesotans ages 60 to 69 went from 8.2 percent to 11.1 percent.

The hospitalization rate is up the most for the oldest Minnesotans, too. Among those 70 to 79, the share of cases hospitalized went from 18.7 percent to 26.3 percent, and among those 80+, from 25 percent to 41.8 percent.

While that jump is large as a percentage, the raw numbers are not. Minnesota saw 2,927 hospitalizations of people 80 or older in November and December, and 246 between late March and mid-April. MDH Infectious Disease Director Kris Ehresmann said many of the people in that age group still getting sick are likely still unvaccinated. It’s also possible they got the virus despite vaccination, which is rare but can happen.

Just as it’s driving the recent rise in COVID-19 cases in Minnesota, the B117 coronavirus variant is likely to blame for the increased hospitalization rates. The variant is believed to make up more than 60 percent of cases in Minnesota at this point.

“I think there’s a sense of, oh there’s the whole world of COVID and then this little streak of variant,” she said. “No, the variant has now become the whole world of COVID. And that means that things aren’t playing out in exactly the same way as they did last fall and we shouldn’t expect them to.”

Not only is the variant estimated to be significantly more transmissible, emerging studies — and Minnesota’s data — suggest it may be causing more severe disease, Ehresmann said.

“The disease that is happening is more severe,” Ehresmann said. “We want people to be cognizant of that.”

Hospitals feel surge

The increase in patients is putting pressure on hospital capacity. “We’re seeing a lot more patients in the hospital than we were a month ago,” Sannes said. “As of today, four times as many compared to March 14.”

This is a busy time with non-COVID hospitalizations, he said, and with COVID-19 hospitalizations rising, too, that’s putting the hospitals much closer to capacity more of the time.

On the plus side, with younger patients, the average hospital stay is decreasing in length, and fewer ventilators and ICU beds are in use, Sannes said.

Hoody echoed Sannes’ concerns, urging Minnesotans to keep their guard up for the next couple months as more people are vaccinated.

“The patient flow is challenging right now,” he said last week. “Everyone on the front lines is fatigued, and that there’s concern that people are going to let down their guard with the standard social distancing and masking precautions just because of the vaccines.”