Protests are important—they are a key medium for illuminating injustices that have long been ignored. Today, protests are being used as critical platforms for advocating against the structures that allow police brutality to persist and to go unpunished. However, as infectious disease epidemiologists, we recognize that protests can multiply the opportunities for COVID-19 transmission. We also know that African Americans already experience significant health inequities, including more heart disease, maternal mortality, and certain cancers than other races/ethnicities, and more deaths due to COVID-19 [1,2]. Thus, instead of discouraging these mass acts of protest, which are necessary if change is going to happen within policing and within healthcare, we encourage law enforcement to practice public health–centered approaches when policing these demonstrations.
At many protests in recent weeks, policing practices may have directly increased contact rates and thus the risk that individuals become infected with COVID-19, promoting increased transmission among protesters and among police officers, and potentially aggravating other health conditions. These practices include forced crowding—on streets, in police cars, on buses, and in jails—and the use of “riot control agents” , like tear gas and pepper spray, rubber bullets, and physical force. These policies can also trigger serious health conditions, especially those tied to cardiovascular and respiratory health.
While protests and rallies inevitably involve some degree of close contact, some policing policies further elevate opportunities for direct interactions and, thus, transmission. For instance, the act of cornering protesters in tight spaces on streets and blocking any form of exit (a practice known as “kettling”) can force considerably greater contact [4,5].
Other dangerous police tactics also increase rates of contact among and between protestors and law enforcement. Forcing large groups of people into police buses  poses a major threat for little gain to public safety, given that most protestors are arrested for simply protesting after curfew . Due to poor air circulation and ventilation, these packed “indoor, confined spaces”  can rapidly distribute the virus. Detained protesters, and the police officers near them, especially those in crowded holding rooms, face a much greater risk of being infected [5,7,8,9]. Additionally, the use of force and acts of assault committed by officers [6,10] increase the risk of transmission due to close contact between the police officer and protestor.
Reports of the use of tear gas, which in some cases is used in addition to kettling, are cause for further alarm. Tear gas, an irritant, provokes coughing [9,11,12,13] and the release of mucus [11,12,13], increasing an individual’s risk of infection and of transmitting the virus if already infected [11,12,13]. This irritation, which can lead to severe itchiness , is likely to prompt people to touch their face more often, increasing contact with the virus. These responses last up to thirty minutes , greatly amplifying the likelihood of transmitting the virus between protestors within the same area. The combination of kettling and tear gas effectively multipliesboth contact rates and susceptibility to infection, with a corresponding pronounced impact on transmission .
Both tear gas and pepper spray can exacerbate other health problems that are especially common in African-Americans, and can make COVID-19 infection more fatal. These agents intensify inflammation [9,11,15] and threaten lung capacity [3,11,15], which can worsen existing health conditions and cause lung congestion , sleep disorders , asthma [9,13], and bronchitis [9,13]. They can further cause eye and heart issues, such as glaucoma, a disease that can result in blindness [9,16], and hypertension (high blood pressure) [9,17]. This is particularly concerning because asthma is already more lethal for African Americans than for any other ethnic group (21.8 deaths/million) . Likewise, the rate of hypertension and the risk of congestive heart failure for African Americans far exceed those of any other ethnicity [18,19]. Many of these comorbidities have further been linked to higher case fatality rates among patients with COVID-19 .
The use of rubber bullets can also result in severe skin, brain, chest, eye, and neck injuries [21,22]. A meta-analysis of rubber bullets and other “kinetic impact projectiles” found that over 15% of those shot experience irreversible consequences, such as blindness and stomach injuries that required surgeries; 2.6% of those who are wounded die of their injuries . These injuries will drive visits to emergency departments, increasing the chance for hospital-based transmission of COVID-19.
We support thorough policy reforms limiting the extent of aggressive law enforcement tactics; these actions will enable protesters to march and speak in peace while limiting the potential for COVID-19 transmission. Those who direct the actions of police can choose—as several mayors have already—to prohibit police practices that enhance COVID-19 transmission.
Police—and protesters—can take action to reduce the risk of COVID-19 transmission. Both police and protesters, by wearing either face shields or face masks and goggles, can limit the transfer of and exposure to the virus during speeches, chants, and other exchanges [11,23]. As has already been shown in some protests thus far, stations with face masks and shields, goggles and hand sanitizer can be extremely useful in better distributing these resources, particularly to individuals who would otherwise not have access to them [11,23,24].
In light of the direct and downstream consequences of certain policing policies during protests, that contribute to both increased contact and vulnerability to infection, we urge officials to reconsider current tactics which can dramatically amplify the spread of COVID-19. These consequences are likely to have even greater impacts on already higher-risk populations, increasing the very inequities that necessitate these protests. Police share a responsibility to maintain safety, security, and order during a protest—a demanding responsibility at any time, and particularly in the middle of a pandemic. However, police brutality at any protest is wrong, and is especially shocking when police brutality is the very subject of the protest. Such policing practices take on an additional level of risk, that of disease transmission, that can threaten both protestors and the police themselves. These longstanding policing tactics are unacceptable and must be halted in the era of COVID-19 for the life, health, and livelihoods of all communities, specifically those who are doubly overlooked and most subjected to systemic racism.
Emma K. Accorsi
Pablo Martinez De Salazar Muñoz
William P. Hanage
Kevin C. Ma
Tigist F. Menkir
Tatum D. Mortimer
Jennifer Lai Remmel
 Zeeshan Aleem, “New CDC Data Shows Covid-19 Is Affecting African Americans at Exceptionally High Rates,” Vox, April 18, 2020. https://www.vox.com/coronavirus-covid19/2020/4/18/21226225/coronavirus-black-cdc-infection
 APM Research Lab Staff, “The Color of Coronavirus: COVID-19 Deaths by Race and Ethnicity in the U.S.,” APM Research Lab webpage, May 27, 2020. https://www.apmresearchlab.org/covid/deaths-by-race
 “Facts about Riot Control Agents: Interim Document,” Centers for Disease Control and Prevention website, April 4, 2018.https://emergency.cdc.gov/agent/riotcontrol/factsheet.asp
 Ali Watkins, “‘Kettling’ of Peaceful Protesters Shows Aggressive Shift by N.Y. Police,” New York Times, June 5, 2020. https://www.nytimes.com/2020/06/05/nyregion/police-kettling-protests-nyc.html
 Alice Miranda Ollstein and Dan Goldberg, “Mass Arrests Jeopardizing the Health of Protesters, Police,” Politico June 4, 2020. https://www.politico.com/news/2020/06/04/police-arrest-coronavirus-301913
 Michael Sainato. “‘They set us up’: US police arrested over 10,000 protesters, many non-violent,” The Guardian June 8, 2020. https://www.theguardian.com/us-news/2020/jun/08/george-floyd-killing-police-arrest-non-violent-protesters
 City News Service, “Anti-Police-Brutality Protests Held Across Southern California; 10,000 Gather Downtown,” NBC Los Angeles, June 4, 2020. https://www.nbclosangeles.com/news/local/anti-police-brutality-protests-held-across-southern-california-10000-gather-downtown/2374433/
 Xia Yu, Shanshan Sun, Yu Shi et al., “SARS-CoV-2 Viral Load in Sputum Correlates with Risk of COVID-19 Progression,” Critical Care 24 (April 23, 2020) 170. https://doi.org/10.1186/s13054-020-02893-8. https://ccforum.biomedcentral.com/articles/10.1186/s13054-020-02893-8
 Craig Rothenberg, Satyanarayana Achanta, Erik R. Svendsen et al., “Tear Gas: An Epidemiological and Mechanistic Reassessment,” Annals of the New York Academy of Sciences 1378 (2016): 96–107, doi: 10.1111/nyas.13141. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5096012/pdf/NYAS-1378-96.pdf
 Catherine E. Shoichet, “Protests Are Erupting over Police Brutality. And Some Officers Are Responding To the Outcry with Force,” CNN, June 5, 2020. https://www.cnn.com/2020/06/02/us/police-protests-use-of-force/index.html
 “Open Letter Advocating for an Anti-racist Public Health Response To Demonstrations against Systemic Injustice Occurring during the COVID-19 Pandemic,” June 2020, signed by 1,288 public health professionals, infectious diseases professionals, and community stakeholders. https://drive.google.com/file/d/1Jyfn4Wd2i6bRi12ePghMHtX3ys1b7K1A/view
 Jessica Glenza, “‘Really scary’: Experts Fear Protests and Police Risk Accelerating Covid-19 Spread,” The Guardian, June 3, 2020. https://www.theguardian.com/us-news/2020/jun/03/protests-police-covid-19-coronavirus-spread
 Lisa Song, “Tear Gas Is Way More Dangerous Than Police Let On—Especially during the Coronavirus Pandemic,” ProPublica, June 4, 2020. https://www.propublica.org/article/tear-gas-is-way-more-dangerous-than-police-let-on-especially-during-the-coronavirus-pandemic
 Ryan Briggs and Max Marin, “Philly Police Say Tear Gas Used Because 676 Protest Turned Hostile, but There’s No Evidence That Happened,” WHYY (PBS), June 2, 2020. https://whyy.org/articles/philly-police-say-tear-gas-used-because-676-protest-turned-hostile-but-theres-no-evidence-that-happened/
 Christopher A. Reilly, Jack L. Taylor, Diane L. Lanza et al., “Capsaicinoids Cause Inflammation and Epithelial Cell Death through Activation of Vanilloid Receptors,” (2003) Toxicological Sciences 73 (2003): 170–181, https://doi.org/10.1093/toxsci/kfg044. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2423488/
 “Glaucoma Facts and Stats,” Glaucoma Research Foundation webpage, October 29, 2017. https://www.glaucoma.org/glaucoma/glaucoma-facts-and-stats.php
 “Asthma,” Centers for Disease Control and Prevention, March 24, 2020. https://www.cdc.gov/asthma/most_recent_national_asthma_data.htm
 Cheryl D. Fryar, Yechiam Ostchega, Craig M. Hales et al., “Hypertension Prevalence and Control Among Adults: United States, 2015–2016,” Centers for Disease Control and Prevention, NCHS Data Brief No. 289, October 2017. https://www.cdc.gov/nchs/products/databriefs/db289.htm
 Hossein Bahrami, Richard Kronmal, David A. Bluemke et al., “Differences in the Incidence of Congestive Heart Failure by Ethnicity: The Multi-Ethnic Study of Atherosclerosis,” Archives of Internal Medicine 168 (2008), 2138–2145, https://doi.org/10.1001/archinte.168.19.2138. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038918/
 Paul G. Auwaerter, “Coronavirus COVID-19 (SARS-CoV-2),” Johns Hopkins ABX Guide, updated June 3, 2020. https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540747/all/Coronavirus_COVID_19__SARS_CoV_2_#32191259
 Rohini J Haar, Vincent Iacopino, Nikhil Ranadive et al., “Death, Injury and Disability from Kinetic Impact Projectiles in Crowd-control Settings: A Systematic Review,” BMJ Open, December 5, 2017, 7:e018154, doi:10.1136/bmjopen-2017-018154. https://bmjopen.bmj.com/content/bmjopen/7/12/e018154.full.pdf
 Lilun Li, “Rubber Bullets Are Touted as a ‘Safe Alternative.’ My Patient’s Wound Tells a Different Story,” Washington Post, June 4, 2020. https://www.washingtonpost.com/opinions/2020/06/04/rubber-bullets-are-touted-safe-alternative-my-patients-wound-tells-different-story/
 Kerry Breen, “How To Stay Safe while Attending Protests,” Today, June 4, 2020. https://www.today.com/tmrw/how-protest-safely-tear-gas-safety-what-wear-more-t183199
 Laura Bliss, “To Sustain the Protests, They Brought Snacks,” CityLab, June 5, 2020. https://www.citylab.com/equity/2020/06/george-floyd-protest-mutual-aid-community-support-free-food/612661/