If people protesting George Floyd's death are getting COVID-19 from being in such close physical contact, the resulting spike in cases wouldn't be visible yet in the daily statistics.

"If we were to see an increase, it might not occur until even next week," Minnesota Health Department Spokesman Doug Schultz said Sunday, noting symptoms of the viral respiratory illness often don't appear until six to ten days after transmission. "It depends on who gets sick, do they get health care, do they get tested."

Minnesota Gov. Tim Walz said the civil unrest sparked by what he has called the "murder" of George Floyd on Memorial Day will lead to more transmission of COVID-19. The City of Minneapolis has made hundreds of masks available to protesters this week, out of concern that one of Minnesota's hardest-hit cities could see even more cases from all the close contact among demonstrators.

Amid a global viral pandemic, Floyd's death has sparked demonstrations worldwide. Atlanta Mayor Keisha Lance Bottoms said people who were protesting Floyd's death in her city probably need to get a COVID-19 test this week, according to NBC News. The mayor also noted that the pandemic has been killing people with black and brown skin at higher rates.

A Star Tribune analysis of Minnesota death records found that people of color are affected by COVID-19 in disproportionate numbers. Although people of color between the ages of 30 and 64 represent 16% of the state population, they accounted for 32% of deaths officially linked to COVID-19 as of early May. Black residents comprised 6% of the state population, and 23% of all confirmed cases.

While rates of confirmed cases of COVID-19 have plateaued or even declined in many states, federal health officials say, Minnesota health leaders are not yet ready to declare new infections have peaked or plateaued in the state.

The Minnesota Department of Health on Sunday announced 664 more confirmed cases of COVID-19, and 14 newly reported deaths caused by the highly contagious viral respiratory illness.

The deaths announced Sunday brought the state's death total to 1,040, as many Minnesota restaurants and salons prepare to reopen with restrictions starting June 1.

Restaurants can open for outdoor service to 50 patrons at a time. Salons may only operate at 25% capacity. It's not yet clear how reopening plans will be impacted by property damage in some commercial corridors, and the closures of major highways and the strict nighttime curfew that Walz extended from 8 p.m. Sunday to 6 a.m. Monday.

The total number of confirmed cases of COVID-19 in Minnesota as of Sunday — 24,850 — doesn't appear to be growing as fast as it was several weeks ago, data from the state show.

But Walz says he's worried that ongoing civil unrest in Minnesota stemming from the videotaped death of George Floyd at the hands of Minneapolis police on Memorial Day would create an environment for COVID-19 to spread quickly. Walz has praised peaceful demonstrators protesting during daytime hours, while condemning agitators descending on the city at night to burn and loot.

"I am deeply concerned about a super-spreader type of incident … after this," Walz said in a news conference Saturday night, after being asked whether the Twin Cities had adequate jail space to safely hold people arrested in the crackdown. "We are going to see a spike in COVID-19. It's inevitable."

But such a spike would not yet be visible in daily case counts, because of the virus' incubation period and delays in how test results are processed and tabulated.

The Centers for Disease Control and Prevention says symptoms of COVID-19 can develop between two and 14 days after initial exposure. In an analysis of 181 cases published earlier this month in the Annals of Internal Medicine, the median time it took to develop symptoms was estimated to be 5.1 days. Some people never show symptoms, though they can still spread the virus.

Also, many COVID-19 tests offered by local health care providers are processed off-site, and can take days to deliver results.

COVID-19 is typically spread via droplets of water in the breath of people who are infected, which is why public-health authorities recommend wearing homemade masks or bandannas to prevent a person from spreading the virus to others. Photos of protesters and rioters in recent days show many people wearing masks, but not all.

As of Sunday there were 257 people with COVID-19 being treated in intensive-care beds in Minnesota, and another 298 who were in regular hospital beds.

COVID-19 is more dangerous for older residents and those living in group settings, as well as for people with pre-existing health conditions including lung disease, serious heart conditions, cancer, severe obesity, diabetes and kidney patients on dialysis. Most people who have died from the illness in Minnesota have had at least one of those conditions.

On Sunday, 11 of 14 newly reported deaths happened to people who lived in long-term care or assisted living facilities. Two were at least 100 years old when they passed away, including one in Hennepin County and another in Dakota County. Everyone who died was at least 60.

State health officials have processed results of 249,519 lab tests for COVID-19 in Minnesota, including just over 7,000 new results added on Sunday to the list. Sunday marked the fourth consecutive day of more than 7,000 test results reported in a 24-hour period.

Of the nearly 25,000 people with confirmed COVID-19 cases, more than 18,000 are now classified in state records as "no longer needing isolation."