Last month’s Sturgis Motorcycle Rally drew upwards of 450,000 attendees to the small city of Sturgis, South Dakota, marking the largest physical gathering since the pandemic began. While many feared the Sturgis would prove to be a “super spreader” event, the true magnitude of the spread is only now becoming known. And it isn’t pretty.
A new study published by health economists Dhaval Dave, Andrew Friedson, Drew McNichols, and Joe Sabia concluded that Sturgis is responsible for 260,000 new cases of COVID-19 – or, 19% of the total number of US cases during the month of August — and $12 billion in new medical care.
“The Sturgis Motorcycle Rally represents a situation where many of the ‘worst case scenarios’ for superspreading occurred simultaneously: the event was prolonged, included individuals packed closely together, involved a large out-of-town population (a population that was orders of magnitude larger than the local population), and had low compliance with recommended infection countermeasures such as the use of masks,” they write.
The economists cite three metrics in determining the total number of cases stemming from Sturgis:
“First, using anonymized cell phone data from SafeGraph, Inc. we document that (i) smartphone pings from non-residents, and (ii) foot traffic at restaurants and bars, retail establishments, entertainment venues, hotels and campgrounds each rose substantially in the census block groups hosting Sturgis rally events. Stay-at-home behavior among local residents, as measured by median hours spent at home, fell. Second, using data from the Centers for Disease Control and Prevention (CDC) and a synthetic control approach, we show that by September 2, a month following the onset of the Rally, COVID-19 cases increased by approximately 6 to 7 cases per 1,000 population in its home county of Meade. Finally, difference-in-differences (dose response) estimates show that following the Sturgis event, counties that contributed the highest inflows of rally attendees experienced a 7.0 to 12.5 percent increase in COVID-19 cases relative to counties that did not contribute inflows.”
In comparison, recent Black Lives Matter protests and Donald Trump’s Tulsa rally did not produce a similar surge in new coronavirus cases, the health economists found in separate studies examining each event. Attendees of BLM protests generally wore face masks and isolated following their participation in the protests. Meanwhile, Tulsa was able to offset the risk of an outbreak stemming from Trump’s rally due to “voluntary closures of restaurants and bars in downtown Tulsa, increases in stay-at-home behavior, displacement of usual activities of weekend inflows, and smaller-than-expected crowd attendance.”
In the case of Sturgis, attendees generally did not wear face masks and congregated in confined spaces (restaurants, bars, Smash Mouth concerts, etc.) over the course of 10-day event, and did not self-isolate once the event was over. As a result, an estimated 263,708 cases of COVID across the country can now be attributed to the rally. Already, one person who attended the rally has died from the virus, but unfortunately that number is also expected to grow.
New @SDSUCHEPS paper by Dhaval Dave @FriedsonAndrew @Drew_McNichols & Joe Sabia ("Contagion Externality of Super-spreader") finds Sturgis Motorcycle Rally was a local & nationwide spreader of COVID-19. Estimated public health cost: ~$12B
— CHEPS (@SDSUCHEPS) September 6, 2020