COVID-19 testing of protesters in the Twin Cities could reshape the world's understanding and response to the pandemic, especially if the result is no increase in cases of the infectious disease.

The assumption following the protests over the May 25 death of George Floyd is that these masses of humanity would spread the novel and highly infectious coronavirus that causes COVID-19, but the proof will come through free testing being offered this month near protest sites in Minneapolis and St. Paul and results from protesters who seek tests from their doctors.

"The data from these events, both in Minnesota and at the broader level, that will all help inform our understanding of how this virus acts and how it affects our population," said Kris Ehresmann, state infectious disease director.

An increase in cases due to the protests would be expected already, in theory, as the incubation period between exposure and onset of symptoms is two to 14 days, and the first large demonstrations following Floyd's death occurred more than 14 days ago.

Minnesota has seen no such surge — the 352 newly diagnosed cases reported on Wednesday represented a slight uptick from Tuesday but were well below the single-day high of about 840 on May 23. Patients hospitalized due to severe COVID-19 dropped on Wednesday to 427, with 193 in intensive care. That is the lowest number since May 4.

The state reported another 19 COVID-19 deaths, though, bringing the toll of the pandemic on the state so far to 1,236 — including 984 deaths of residents of long-term care and assisted-living facilities.

The reopening of Minnesota amid the pandemic accelerated Wednesday with bars and restaurants allowed to offer limited indoor service, and fitness clubs, movie theaters and bowling alleys allowed to operate at 25% capacity. All must limit their number of customers indoors to 250 and maintain social distancing restrictions that keep unrelated groups 6 feet apart as much as possible to reduce the spread of the virus.

The next step could come before July 4 and permit competitive youth sports, overnight summer camps and pro sports without fans in the stands, Gov. Tim Walz said on Wednesday.

"It is going to be dependent on where the numbers are," said Walz, forecasting a decision by June 20.

The state last week recommended COVID-19 testing for people five to seven days after their participation in mass protests that present exposure risks, regardless of whether they have any respiratory symptoms that suggest infection. Previously, the state had prioritized testing for people with symptoms and workers and patients in hospitals and long-term care facilities.

A lack of an increase in cases caused by protests would bolster the theory that the novel coronavirus doesn't spread as easily in the outdoors or in hot, humid air. Ehresmann said the state will be looking for signs that protests in other states influenced their COVID-19 cases and would adjust tactics based on those results.

"We will be looking at that to see if that will help inform future decisions," she said.

Health officials are pleased there has been no sustained surge in cases following Walz's earlier decision to lift a statewide stay-at-home order after 51 days on May 18. Cases did peak over the Memorial Day weekend — with some Twin Cities hospitals briefly filling up all of their intensive care beds — but daily case growth has subsided.

Health officials said they will be watching Minnesota's progress following the latest reopenings, especially following upticks in COVID-19 hospitalizations in states that were further along in scaling back restrictions.

"There's been some attention, just lately, to Arizona and Utah, for example, and what might be learned from the sudden rise that we're seeing in those states," said Jan Malcolm, state health commissioner.

Minnesota is in the middle when compared with other states in terms of COVID-19 cases and deaths, but it has more deaths than Wisconsin, even though the border state is more populous and had its stay-at-home restrictions thrown out by a court order in mid-May.

Ehresmann said that could be due to fewer outbreaks in long-term care facilities — where elderly residents are at greater risk of severe COVID-19 cases — or in food processing plants where the virus can quickly spread among workers. Epidemiologists from the two states have been talking about the differences in their responses and results.

Minnesota officials reported progress in reducing COVID-19 in long-term care facilities, which in this state include skilled nursing homes and other group residential facilities. Aggressive testing of residents and workers has sought to identify cases in those facilities before they spread.

The number of new facilities reporting outbreaks has declined from 23 per day five weeks ago to five per day now, Malcolm said. Statewide, cases have been reported in 36% of skilled nursing facilities.

Despite the positive trends, many businesses were slow to reopen on Wednesday despite state permission to do so. Many needed more time to train staff and adjust their facilities to maintain social distancing at levels that will make customers comfortable, said Steve Grove, commissioner of the Minnesota Department of Employment and Economic Development.

"It's not as if people are all sprinting at once to go back to the restaurants," he said. "Today is not the grand reopening of the entire Minnesota economy. It's the beginning of a process."

Grove said maintaining social distancing is the key. Movie theater complexes could technically have up to 250 people in each theater but have to arrive at a number that allows for required spacing.

Health officials said increasing testing levels — and lower rates of tests turning up positive — are good indicators that COVID-19 growth is manageable right now. The 8,859 tests reported by the state on Tuesday represented a record for that day of the week.

Free testing clinics will continue in Minneapolis and St. Paul on Tuesdays and Wednesdays for the next two weeks, primarily for protesters and others involved in mass events.

The state is looking to expand capacity of those clinics following long lines and heavy interest this week. Appointments are recommended, as the clinics offer limited walk-up opportunities.

Staff writer Glenn Howatt contributed to this report.