The word “unprecedented” has been used ad nauseam in recent months, but when public health authorities tried on Sunday to predict the potentially catastrophic effect of nationwide police brutality protests amid a deadly pandemic, it seemed hard to find a suitable alternative.

After months of diligent social distancing to curb COVID-19 transmission, Americans in major cities all over the country took to the streets in huge crowds this week to protest the death of George Floyd—and decades of other black deaths at the hands of police officers—after the 46-year-old was killed by a white Minneapolis police officer who shoved a knee into his neck while he was handcuffed, face-down on the pavement.

Public health experts and city leaders now fear new waves of COVID-19 outbreaks could worsen infection numbers and deepen racial disparities among those severely sickened by the virus.

Protesters, reporters, and police officers were injured in the swelling demonstrations that led to curfews in more than 25 major metropolitan cities from Colorado and Tennessee to Florida and Kentucky and Ohio. The national guard was deployed in Minnesota, Georgia, and the cities of Chicago and Los Angeles.

Atlanta Mayor Keisha Lance Bottoms urged demonstrators in her city to seek COVID-19 tests after attending protests, especially considering the mounting evidence that the pandemic is “killing black and brown people at higher numbers.” Bottoms told CNN’s Jake Tapper, host of State of the Union, on Sunday morning that she is “extremely concerned” about COVID-19 spikes in the coming weeks.

“We are losing sight of so many things right now,” said Bottoms. “Losing sight of the fact that there has to be change in this country as it relates to race relations in this country. There has to be change in this country when it comes to leadership in this country. There has to be change as it relates to our health-care system and how our communities of color are receiving health care in this country. But right now, we’re talking about cars being burned and businesses being vandalized. And there’s still so many issues that are right before us that we’ve lost sight of.”

Though many states continued to phase out of stay-at-home orders this month, nearly a dozen last week were experiencing increases of daily case counts for the deadly virus, which had infected more than 1,773,020 Americans and killed more than 103,853 as of Sunday morning.

Minnesota’s health commissioner and Minneapolis Mayor Jacob Frey have both warned that the protests will likely create a spike in infections, sandwiching one crisis on top of another. Minnesota Gov. Tim Walz on Saturday said he worried that protesters were not adequately socially distancing or wearing masks during demonstrations.

“I will continue to stress, because it seems like a lifetime ago: We are still in the middle of a pandemic and passed 1,000 deaths yesterday,” said Walz. “We still have hospitals on the verge of being overrun with COVID-19.”

Those concerns were echoed on Sunday by city leaders from Los Angeles to Baltimore, and public health experts agreed that very serious outbreaks could follow this week’s nationwide demonstrations.

“It’s pretty likely,” said Dr. Brittany Kmush, an assistant professor at Syracuse University who specializes in epidemiology, global health, and infectious diseases. But it’s “hard to predict” what areas might see the worst spikes in the next several weeks because there’s no historical precedent for mass civil unrest in the midst of a global pandemic. However, there are several factors that might help to prepare public health departments, Kmush told The Daily Beast.

Authorities should watch those areas with the longest lasting protests, said Kmush, in addition to those with the most participants, shouting or singing, physical contact, and travel.

“Whenever you have a big gathering of people, that’s the catalyst,” said Kmush. “If you have one person who is incubating or sick, they can spread it to quite a few other people.”

But protesters have said time and again in interviews that they understand the gamble they’re making. 

“It’s not OK that in the middle of a pandemic we have to be out here risking our lives,” 25-year-old black woman Spence Ingram told the Associated Press on Friday in Atlanta.

Though Ingram has asthma and is worried about what may happen if she contracts the virus, she told the news site: “I have to protest for my life and fight for my life all the time.”

Kmush’s advice to those in the streets? Wear masks, maintain as much distance as possible, and think about who you might be exposing at home or at work. 

“If you’re out protesting and normally take care of an elderly relative, try to get someone else to do that for a few weeks. Balance your risk with the risk of those people you come into contact with frequently,” she said.

How protesters travel to the events will be “important” in predicting outbreaks, said Lawrence Gostin, who directs the O’Neill Institute for National and Global Health Law at Georgetown University and the World Health Organization’s Collaborating Center on National and Global Health Law. “If they’re stopping in restaurants, using public bathrooms, and taking public transportation, all of those things are helping the virus move from one place to another because humans are vectors,” he explained. 

At the individual level, said Gostin, “If you insist on going, wear disposable gloves, wear a mask, and stay 6 to 10 feet away from any other protesters. When you leave, make sure you self-isolate and wash your hands thoroughly.” For public health authorities, Gostin said community-based random testing is the best way to create an early warning system for new outbreaks.

“We know this is likely to be an amplifying event, and if we don’t get a handle on it very quickly it could spread out of control,” he added. “We have to be careful that racial injustice isn’t compounded by health injustice.”

In another complication on Sunday, “safety worries” over the unrest in Los Angeles reportedly led to a citywide closure of COVID-19 testing centers. But despite the risks, even medical professionals have been willing to jump into the fray.

As a doctor dressed in scrubs and protesting at Barclays Center in Brooklyn told a reporter on Friday: “How can I save someone’s life if a police [officer] kneels on their neck?”

Dr. Rob Davidson, an emergency physician at a hospital in West Michigan, said he felt it was his “duty” as a doctor and a father to attend a Black Lives Matter protest in Muskegon on Sunday when he finished his shift. 

“Being black in America is a public health emergency,” Davidson told The Daily Beast. “When you look at the number of lives lost to structural racism in this country, it’s worse than anything that COVID-19 has done.”

“I’m finding it very difficult to know really what to do—or what anybody would recommend,” said Dr. Irwin Redlener, director of the National Center for Disaster Preparedness at Columbia University and an expert on U.S. readiness for pandemics. “It’s so important for people to acknowledge the long history of abuse and disparities that have been experienced by African Americans, and there’s no question that low income and minority populations are suffering—and will be suffering—the greatest impact of the virus.”

While Redlener told The Daily Beast on Sunday that he wasn’t aware of any documented studies showing what happens when tear gas is combined with the novel coronavirus, there’s evidence of at least short-term lung damage, which mixed with an upper-respiratory disease could be dangerous.

“People that are protesting are under a great deal of psychological stress, in far too close proximity to other people, and they are getting exposed to tear gas, which may put them at greater risk for severe infection if their lungs are damaged,” he said. (Kmush agreed with that assessment, saying: “I can see how a lung irritant and this virus at the same time would not be a good combination, but I don’t think we know yet how the two will interact.”)        

But Redlener compared the decision to protest—at the intersection of these risk factors—to choosing to run back into a burning building to save a child.

“I’m not sure what the advice would be—that you have to ignore that? That we’re having a pandemic, so you don’t protest? You have this tinderbox that exploded with this killing,” he continued. “People put pandemic concerns to the side while they go to the streets and express anger, not just about Minneapolis, but about the past 400 years of being African American in America.”

“Do what you have to do, and we’ll deal with it afterwards,” said Redlener.