Eleven more deaths from COVID-19 were confirmed by the Minnesota Department of Health Thursday — the highest one-day total in the state since the pandemic started.

The deaths, which bring the state's total to 50, include 10 residents of long-term care facilities and seven people who lived in Hennepin County. All were between the ages of 70 and 99.

The jump in deaths came one day after Gov. Tim Walz extended a statewide stay-at-home order until May 4 to try to delay the peak of the pandemic in Minnesota until summer. The order, originally scheduled to end Friday, seeks to reduce face-to-face contact and viral transmission by 80%.

Michigan once had comparable numbers to Minnesota before they "shot through the roof," the governor warned. "We cannot rest easy. This thing can explode overnight if you don't take the proper precautions."

The COVID-19 outbreak has defied expectations in some ways, including shorter hospital stays for severe cases and a lower-than-expected rate of fatal illnesses. On the other hand, the novel coronavirus has spread far more rapidly than expected — with one infected person spreading it to as many as four others.

Minnesota now has 1,242 lab-confirmed COVID-19 cases. The outbreak continues to mirror global trends of COVID-19 cases being harsher on the elderly and people with underlying health conditions. The median age of Minnesota's lab-confirmed cases is 51, but the median age of fatalities is 87. In an initial study of 28 of the COVID-19 deaths, 27 involved people with underlying conditions such as diabetes or asthma.

No deaths have been reported among health care workers.

Modeling by the University of Minnesota and the Minnesota Department of Health suggests the state might run short of intensive care beds at the expected peak of COVID-19 cases. The stay-at-home goal is to reduce or delay that peak until around June in Minnesota, giving hospitals time to add beds, personal protective equipment for doctors and nurses, and ventilators that substantially increase the odds of survival when patients with severe respiratory symptoms need them.

Walz said he was confident that Minnesotans will comply with the new, longer order — despite criticism Thursday from Republican State Senate Majority Leader Paul Gazelka that the state already has enough hospital beds and is overpreparing for a New York-style outbreak that won't happen here.

The governor also said he heard rumors of people trying to get the infection in order to move on from it, and called that a "really bad idea."

While one in five people with the infection might have no symptoms, and four in five might have only mild symptoms, Walz said people have to be sensitive to the needs of others at greater risk.

"You may be fine and you may have your free will and you going out may kill someone else's family," he said.

Economic pain fuels criticism

Walz acknowledged the economic pain of the pandemic and the stay-at-home order, which shut down dine-in restaurants, closed schools, and pushed more than 380,000 Minnesotans to apply for unemployment benefits.

The initial order exempted 78% of jobs tied to critical industries, and the governor pledged this month to review situations in which other workers can return to their jobs with minimal risks of spreading diseases. He mentioned the theoretical example of opening boatyards if they could stagger clients so they don't come in close contact.

But the lingering economic pain has fueled criticism.

State Sen. Scott Jensen, a physician and Republican from Chaska, has criticized the state health department for following federal guidance on when doctors should characterize deaths as due to COVID-19. His concern is that the direction might push doctors to overdiagnose COVID-19, inflate the death toll and prolong the invasive social-distancing measures.

Among those strongly disagreeing with Jensen's argument on Thursday was Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, and a leader of the federal COVID-19 response.

"There is absolutely no evidence that that's the case at all," said Fauci, responding in a televised NBC interview to the general theory, not Jensen specifically. "I think it falls under the category of something that is very unfortunate — these conspiracy theories that we hear about."

Concern over false negatives

While treating physicians or medical examiners declare causes of death, they routinely receive guidance from health authorities on how to make those decisions — particularly when new cause-of-death codes are added to the International Classification of Diseases guidebook. The code for COVID-19 was added April 1.

The latest federal guidance sought to increase consistency in reporting of COVID-19 deaths, which helps define the scope and breadth of the pandemic, said Jan Malcolm, state health commissioner.

"It's really important that there is as much consistency as we can get on this," she said, "because that accuracy helps us get a better understanding of the real prevalence of this disease — especially at a time when the testing process is still more limited than we would like. … We know that test-confirmed cases are the tip of the iceberg."

Some health officials have raised concerns about an opposite trend — an underreporting of COVID-19 cases and deaths because of false negative results by the reverse transcriptase-polymerase chain reaction (RT-PCR) test for COVID-19.

Mayo Clinic researchers on Thursday published concerns about how a sensitivity rate as high as 90% in testing would still result in many people being falsely diagnosed as not being infected — given the rapid spread of the virus.

"RT-PCR testing is most useful when it is positive. It is less useful in ruling out COVID-19," said Dr. Priya Sampathkumar, a lead author of the report in the journal Mayo Clinic Proceedings. "A negative test often does not mean the person does not have the disease, and test results need to be considered in the context of patient characteristics and exposure."

Minnesota's public health lab has accounted for the false negatives from the federally provided test kits in letters sent to patients, said Joanne Bartkus, lab director.

"Our test result comes with a disclaimer that says that a negative result does not mean you're not infected with coronavirus," Bartkus said. "We cannot rule that out. So that's a caveat of the test."

Higher rates of false negatives with two of the testing platforms also prompted the state lab to stop using them, she said. That further hindered the testing capacity of the state lab, though, which like other labs was already struggling with shortages of collection swabs and testing chemicals.

Walz said increased testing will be a key part of the state's emergence from the pandemic, and he has proposed a "Minnesota moonshot" to not rely on federal supplies and to instead develop large quantities of antibody tests within the state that can determine when workers have recovered from COVID-19 and are safe to go back to work.

Staff writer Glenn Howatt contributed to this report.