When the killing of George Floyd sparked a renewed round of Black Lives Matter (BLM) protests in May, new Covid-19 cases were stable in the United States. Shortly afterward cases started to increase. Opponents of the BLM movement pinned the blame on the protests, but even many supporters were worried that the mass gatherings helped the virus to spread. Now, however, scientists have presented evidence that indicates the protests did not make a city more likely to experience an increase in cases and may even have made them slightly safer. They also propose an explanation for this counterintuitive observation.
Those seeking to link the protests to the spread of SARS-CoV-2 may have had an agenda, but their case was also not implausible. Although BLM protests generally happened outside and most protestors wore masks, the scale of some of the protests and the often close crowding provided opportunities for transmission. Coughing caused by teargas or the imprisonment of people arrested at the protests also greatly increased these risks.
Yet even to the untrained eye, there was always a problem with the narrative BLM protests were responsible for the June surge. The protests were most intense in Minneapolis, where Floyd was killed, as well as liberal cities like Seattle and Portland. The new cases at the time were concentrated in Arizona and Florida. A team led by Professor Dhaval Dave of Bentley University decided to put some statistical expertise into researching the question of any connection.
As part of the National Bureau of Economic Research Working Paper Series, Dave and co-authors compared 315 US cities' protests and their subsequent case numbers. They found no statistically significant difference in Covid-19 cases in the following month for cities with and without protests. The non-significant difference was for protest-hosting cities to have slightly fewer Covid-19 cases per 100,000 residents, allowing for trends beforehand.
The likely explanation lies in cellphone movement data, which showed that those who did not participate in the protests traveled less, an effect that started three days after the protests began and lasted for weeks. In part, this can be attributed to curfews and other protest suppression measures by local and state authorities. However, aside from these legal responses, cities with large protests also saw less movement and mingling.
Whether the change in behavior was a result of fears of violence and blocked traffic or business shut-downs and boycotts in solidarity with the protest goals is not known. Either way, protests achieved what health officials' warnings had not managed, and the result was Covid-19 spread equally or slower in cities with major protests than cities without, the paper concludes. Cities where there were reports of violence associated with protests had larger increases in people staying home, but so did locations where the rallies were non-violent but well attended or where they occurred over a greater number of days.