When tens of thousands of people hit the streets protesting the police killing of George Floyd, many worried that the crowds—often too dense to allow the recommended 6 feet of social distancing—would spark a new wave of COVID-19 cases. Yet in New York, city and state officials tell me, there have been no spikes of the illness.
Nor have there been sudden surges in several other cities where large demonstrations were held, including Minneapolis, where Floyd was killed and the first protests erupted, and Philadelphia. Spikes have occurred elsewhere—especially Texas, Arizona, Florida, and California—but they coincided with the reopening of bars, restaurants, and other indoor establishments, making it hard to trace the upticks to the protests.
The absence of surges in the cities with massive demonstrations but few other large gatherings has taken many officials and health analysts by surprise. However, as they’ve examined the data and the video footage, one thing has clarified matters, to an extent: A large percentage of the protesters wore masks.
Several recent studies have suggested that masks may be the single biggest impediment to the spread of the coronavirus. What’s new in the data about the demonstrations is that social distancing may be much less important, may be not much of a factor at all—at least if the crowds wear masks and the crowding takes place outdoors.
The possible implications are profound. They suggest that a much wider range of outdoor activities—sports events, beaches, swimming pools, playgrounds, and so forth—could be safely permitted much sooner than currently scheduled. As a result, New York officials are contemplating an expansion and acceleration.
However, officials emphasize that this review applies only to outdoor activities, not to concentrations of people indoors—and that, even outdoors, masks should still be worn.
Jeffrey Shaman, director of the climate and health program at Columbia University and the author of widely publicized studies on the spread of COVID-19, told me in a phone conversation Wednesday, “I think, personally, that the lion’s share of infection occurs indoors. I think that outdoors, in sunshine, with masks, is a fairly safe environment.”
Shaman said that he and his team at Columbia modeled the demonstrations as they were occurring, to see whether they could lead to a surge in COVID-19 infections. They ran their model through three scenarios, each with a different premise on how much masks and the open air would suppress transmission of the virus. In the scenario of lowest suppression, there should have been a substantial bump of cases by now, nearly three weeks after the protests began. In the medium scenario, there should have been a slightly lower bump. In the scenario where masks and open air suppressed the transmission to the greatest degree, there was no bump. “That’s what we’re actually seeing,” Shaman said. “The most optimistic scenario turned out to be most accurate.”
There are caveats to this news, expressed by Shaman and by New York officials. First, they note, the vast majority of protesters were young. Given that people above the age of 50 are more likely to get sick when exposed to the virus, it is not clear that an older crowd would have emerged equally unscathed.
Second, Shaman stops short of endorsing large outdoor events of all types. “Beaches—you’ve got open air, sunshine, people spread out on blankets—that’s OK,” he said. “A baseball stadium—people lined up shoulder to shoulder, semi-indoors, for hot dogs and beer and for crowded restrooms—I’m not so crazy about that.”
Still, Shaman, who advises New York officials on health matters, thinks most purely outdoor events, even large, fairly dense ones, could be held—as long as people wear masks and as long as the people themselves were not in categories of high risk, such as old age or underlying health conditions.
The virus may be less dangerous outdoors for a number of reasons. Infectious droplets can drift in the wind and diminish in sunlight. By the same token, they can build up indoors, especially in places with narrow walkways and poor ventilation.
Still, it is hard to parse the precise effect of the various mitigating factors—masks, distancing, fresh air, sunshine—and even harder to parse the effects of those factors on different people with varying ages, immune systems, blood types, and so forth. “In all of these calculations,” Shaman cautioned, “there’s still a lot of uncertainty.”
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