Why It Would Be Hard to Link a Coronavirus Spike to Recent Protests

After months of being cooped up at home to prevent the spread of coronavirus, people have taken to the streets by the thousands over the past few weeks to protest against police killings of Black people and decades of systemic racism. The gatherings have some people worried about a spike in coronavirus infections—but they have also been defended by some public health experts, who argue that racial injustice is itself a major public health threat.

The risk of transmitting coronavirus is likely lower outdoors, and many of the protesters have been wearing masks. But some experts note there is still risk—especially given the close interactions between police and protesters, the use of chemicals such as tear gas and pepper spray that irritate the mucous membranes (causing tearing, runny noses and coughing), and the corralling of arrested protesters in crowded vans and jail cells.

There is not much evidence that the protests have caused spikes in coronavirus infections so far. And any increase in cases from the protests would be hard to separate from the fact that states are reopening in general, according to Caroline Buckee, an associate professor of epidemiology at the Harvard T.H. Chan School of Public Health. Scientific American spoke with Buckee about the risks posed by protesting, the difficulty of tracing infections back to the protests, and how to stay safe while exercising one’s democratic rights.

[An edited transcript of the conversation follows.]

Is it possible to tell whether a spike in infections was due to the protests, or the relaxation of other restrictions?

The protests have occurred against the backdrop of [states] reopening. In some states, we’re already almost back to kind of usual levels of mobility. And of course we had the Memorial Day weekend, which we know brought a lot of people out and mixing in ways that would enhance transmission. In many of the states where we’re seeing the largest increases [in coronavirus cases], such as Arizona and Florida, in fact, people were starting to move around and interact before the protests. So, it’s somewhat difficult to disentangle cases directly arising from the protests versus just opening up of society in general.

[In addition] the protesters are generally young. And that means that many of them won’t have symptoms, or will have symptoms that are mild enough that they don’t go to a health care facility, so then [the cases wouldn’t be recorded]. The people who are being hospitalized and dying of COVID are elderly people and those with comorbidities. So the impact of the protests—or of any of these gatherings, whether it’s Memorial Day weekend or just reopening—it might take a little while to reach the people who will show up at the hospital who are elderly and otherwise unhealthy populations.

What are the risks posed by protesting?

We know that people crowding together is a risk for transmission, although being outside is better than being inside, of course, and a lot of the protesters did make an effort to social distance and wear masks. Nevertheless there were a lot of things that we think would be a high risk for transmission. And some of those things were the response to the protests, such as being crowded together in vans, being crowded together in jails, tear gas, and so on. So, were there risks associated with the protests? I would say, “Yeah.” I think it remains to be seen what impact that will have had on transmission.

It’s interesting that in New York, we haven’t yet seen a massive uptick in cases—but it might just be that there’s a time lag between transmission and [new] cases, and symptoms and hospitalizations. [Editor’s Note: A representative for the New York City Department of Health said data on the number of coronavirus infections linked the protests was not yet available, but noted that those who attend protests are eligible to get tested at a number of centers around the city.] I do think that, in terms of the risks people are taking, the right to protest is an important function. And just as we prioritize essential workers, we should prioritize essential functions [of] democracy. So I personally support the idea behind the protests, even though I do think that there is some risk when you bring a lot of people together.

The protesters are largely weighing multiple health risks, including the health risk of being Black in America. And presumably, given the emphasis on social distancing and mask wearing by many of the organizations behind the protests, it’s reasonable to assume that many of the protesters are aware of the risks and would be actively trying to prevent spread to their elderly relatives and friends.

There are reports that police themselves do not always wear masks. Is that a risk for the protesters?

Yeah—if we start with the premise that the right to protest is an essential function of our democracy, and [that] it’s the function of the police to protect people, then [it follows that] it’s the function of the police to protect protesters who are exercising their democratic rights. So, [the police] should absolutely be making sure that their policies for controlling the protests do not enhance transmission and [that] they themselves are taking precautions, including wearing masks. And all of these practices, such as putting people in jail cells and crowding people together—those are irresponsible.

How effective do you think masks are at protecting people if they’re outside and aren’t within a few feet of each other?

Masks are tricky. The scientific evidence on [them] has been limited. There isn’t really strong data, and a lot of the data that there is is about mask use in a clinical setting, not in a community setting. Having said that, I think generally the recommendation to wear masks is a good one because we have enough plausible, mechanistic reasons to think that they are useful at preventing droplet transmission. So I think masks plus social distancing are a good general policy.

How would you advise individuals that might be considering attending a protest to evaluate their risk from COVID-19?

It’s really tricky, and everybody has to weigh up their own risks and balances. I think if you are in a household where you have elderly parents or elderly relatives who are very vulnerable, then you may seriously want to consider all the steps that you can take, [including getting] tested after the protest, or quarantining away from them after you’ve attended a protest to protect them. Thinking about your own social network in your own household structure is an important first step. Who are you putting at risk, in addition to yourself, when you attend a protest? And then, of course, taking as many precautions as you can, and doing some research ahead of time to figure out the route you’ll take and all of those kinds of things. And most of the organizations [leading the protests] have put out pretty clear guidelines about actual behavior during the protests around social distancing and wearing masks and so on.

I think there’s a stark difference between [the Black Lives Matter] protests, where there’s an explicit messaging around social distancing and masks, and the anti-lockdown protests, which were explicitly against the public health measures—they encouraged people not to wear masks and not to social distance. That intentional messaging does matter.

If people have attended a protest, should they get tested for COVID-19?

Absolutely. The important thing there is to remember that you have to wait a few days [before getting a test] because it takes a few days for the viral load to increase enough for the test to be able to detect it. So, don’t get the test the very next day, get your test three to four days later.