Deaths and COVID-19 illnesses continued to increase in Minnesota on Tuesday, as the state completed its fourth day of "stay-at-home" restrictions meant to slow the pandemic in the state.

The deaths of two people, aged 83 and 73, in Hennepin County brought Minnesota's total to 12. The state also reported 53 more confirmed infections with the coronavirus that causes COVID-19, bringing the total case count to 629. Health officials also reported 173 confirmed cases among health care workers, though only one case involved someone likely infected while treating an infected patient.

Whether the stay-at-home order by Gov. Tim Walz is slowing the spread of COVID-19 is unclear, because anyone showing symptoms today was likely infected well before the order took effect Friday.

The governor said he is hopeful the strategy is working because most Minnesotans are complying, although there have been reports of crowds, "especially around the lakes." He urged people against complacency.

"This is one of the biggest differences that we can make," Walz said.

State analysts have predicted that compliance with the restrictions could reduce face-to-face contact and the threat of virus transmission by 80%. Earlier this week, state health Commissioner Jan Malcolm said "we're going to know more in a week to 10 days" about whether the restrictions are working.

The order will remain in effect until April 10 and will be followed under current plans by three weeks of social distancing measures and the continued closures of dine-in restaurants, entertainment venues and schools.

After that, restrictions might only remain for people at high risk of complications from COVID-19, including residents of long-term care facilities that are experiencing a rising number of outbreaks.

State health officials Tuesday reported 39 outbreaks in congregate living facilities such as nursing homes, and that infections have been confirmed in 33 residents and 19 workers.

While 80% of COVID-19 infections cause only mild symptoms, the elderly are at higher risk for more severe complications.

The median age of people with confirmed COVID-19 illnesses is 46 in Minnesota, but the median age of hospitalized cases is 63. Among those who have died, the median age was 86.

A new report from the U.S. Centers for Disease Control and Prevention examined more than 7,000 U.S. cases of COVID-19 and reaffirmed the risks to the sick and elderly. People with at least one underlying condition, such as diabetes, represented 37% of overall COVID-19 patients, but 78% of those needing intensive hospital care. Just being older than 65 was a risk factor for needing intensive care.

While health care workers represent a quarter of the confirmed COVID-19 cases, that is largely due to the fact that Minnesota's public health lab is conserving diagnostic testing for them along with hospitalized patients and long-term care facility residents.

Nurses and leaders of the Minnesota Nurses Association have repeatedly expressed concerns about the on-the-job risks, though, because hospitals are already short of the most protective N95 masks and have instituted protocols to reuse masks and gloves in certain situations.

Unionized nurses issued a no-confidence vote last week against M Health Fairview, stemming from negotiations over the transfer of nurses to Bethesda Hospital in St. Paul, which has been converted into a dedicated 90-bed COVID-19 hospital.

The union wanted hazard pay and safety protection guarantees for those nurses.

"We're willing to [care for these patients]," said Emily Allen, a nurse who moved to Bethesda because she wanted to help. "We just need to be safe about it."

Shortages are concerns for Allina Health as well, which is adding roughly 700 computer tablets in its hospital emergency rooms, and later to its intensive care and other units, so that doctors and nurses can videoconference with confirmed or suspected COVID-19 patients when their physical presence isn't needed.

This reduces the threat of viral transmission and conserves masks and other protective gear, said Tom Bethke, Allina's vice president of IS infrastructure.

Maintaining enough "protective equipment is a challenge everywhere," he said, "and if we all use less, we all save more."

Walz on March 20 had expressed hope of preventing the growth of COVID-19 cases in Minnesota from looking like a hockey stick — a gradual uptick followed by a steep and continued increase. Confirmed cases were at 115 on that date, and have increased fivefold since.

While its possible the current stay-at-home strategy could curb that trend, Walz said its main goal is to delay any surge of cases for several weeks — perhaps into May or June.

That would buy time for hospitals to address shortages of masks, and of ventilators to treat breathing problems in severe COVID-19 cases.

On Monday, the state Health Department reported a statewide total of 2,225 ventilators. Of those, 1,230 adult ventilators were in use. A lack of ventilators has been a key problem in countries such as Italy that have seen overwhelming surges in virus cases.

Data modeling by state health and University of Minnesota researchers on potential death and illness rates has assumed a 1.5 to 16.5 times greater risk of death (varying with age) when COVID-19 patients need ventilators and they aren't available.

As of Tuesday morning, 56 of Minnesota's COVID-19 patients were in hospital care — and 26 required intensive care. In 288 cases, Minnesotans have recovered and are no longer required to isolate themselves to prevent the spread of infection.