Protests did not spread COVID-19, but why?

When millions of people streamed into the streets around the world to protest the murder of George Floyd at the hands of a Minneapolis police officer, it gave a sinking feeling to public health officials, whether or not they supported the cause behind the demonstrations.

“It’s a perfect setup for further spread of the virus,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in the United States, in early June. “I get very concerned, as do my colleagues in public health, when they see these kinds of crowds. There certainly is a risk. I can say that with confidence.”

But it never came to pass. Hundreds of cities saw protests in North America earlier in the month, but it’s hard to trace even a single outbreak to the rallies. Vera Etches, Ottawa’s medical officer of health, confirmed this week that not even a single new infection could be attributed to the recent demonstration in the city.

Some experts have speculated that outdoor transmission is so rare with COVID-19 that even a highly risky event such as a protest is relatively safe, especially compared to large events held indoors.

The first study into the phenomenon argues that another factor could be important: the protests never turned into super-spreader events because they encouraged everyone else in the city to stay home. The effect was durable, often as long as a week, which is longer than the average incubation time of the novel coronavirus. The net effect of the protests was that, on average, more people stayed home during the week they were held than the previous week, even accounting for all the people who went out to protest.

The protests themselves seem to be the perfect environment to spread a virus. It’s difficult to socially distance, people are chanting and singing and, in some cities, police officers deployed tear gas, which induces coughing fits. All those activities help spread the droplets that transmit the virus.

The researchers, who released the study at the National Bureau of Economic Research in the United States this week, said it’s possible that the demonstrations caused an uptick of infections among people who attended but that it doesn’t seem to have spread into the general population.

The researchers used cellphone data to track people’s behaviour, so they can only guess as to why people stayed home during the protests.

It could be an effect of traffic congestion caused by marches spilling into the streets, or the fact that many businesses closed, causing employees and customers to stay home.

It could also be that people were concerned about contracting COVID-19 after media reports about the potential for spread of the virus.