From The Atlantic:
The wave of mass protests across the United States will almost certainly set off new chains of infection for the novel coronavirus, experts say.
The virus seems to spread the most when people yell (such as to chant a slogan), sneeze (to expel pepper spray), or cough (after inhaling tear gas). It is transmitted most efficiently in crowds and large gatherings, and research has found that just a few contagious people can infect hundreds of susceptible people around them. The virus can spread especially easily in small, cramped places, such as police vans and jails…
Since chanting seems to spread the virus, [computational epidemiologist] Majumder recommends that protesters use noisemakers, drums, and written signs. She also recommended that protesters carry shatterproof goggles and a saline spritz, in case they are pepper sprayed. “Soothing the irritant with a sterile solution can reduce coughing and sneezing, which are some of the major pathways through which the novel coronavirus is spread,” she said.
Ultimately, however, the responsibility to prevent the spread of COVID-19 rests not with protesters, but with the police and government officials, [professor of global health law] Phelan said: “The state is the one with the duty to protect public health.” Police departments therefore must drop certain tactics that they might normally adopt for crowd-control reasons, she said. “If they are channeling crowds into tight spaces for security and control; if they’re removing their masks; if they’re preventing protesters from using drums or amplified music instead of using their voices, which we know are a vector for transmission; or if they’re arresting protesters and holding them in jail … these potential activities that police are using for security and control of a protest might in themselves increase the risk of transmission of COVID.”
…If the protests cause a spike in COVID-19 infections, the data may not fully convey that factor. Minnesota, the epicenter of the unrest, is already a hot spot for coronavirus infection. There were more COVID-19 deaths on average in Minnesota this week than in any previous week of the pandemic, and the state’s hospitalization rate has never been higher since the pandemic began. Because of lags in reporting the data, and because several days pass before someone infected by the virus begins to experience symptoms, those cases and hospitalizations almost entirely represent people who were infected by the virus before the protests began.