In early August, almost a half-million Americans from all around the country gathered at the annual motorcycle rally in Sturgis, South Dakota.
Many of them took something extra home to share with their communities: COVID-19.
In a time where almost everyone is heeding the CDC guidance or a state mandate against large gatherings, the 10-day Sturgis rally in early August was a big middle finger to good sense and personal responsibility.
The people who went crammed into bars and restaurants, and gathered in large groups in and out of doors. They attended some 30 concerts and parties. Few wore masks or seemed to worry much about social distancing, as the news coverage made clear.
Taking place in a state with one of the laxest of responses to the coronavirus – no shut-down or mask orders – the rally produced exactly what epidemiologists prophesied: an outbreak of COVID-19.
That outbreak didn’t stay in Sturgis. It rode the hogs back home with those who attended the rally, driving up case counts in those communities that had a lot of people attending the rally – including here in Spokane, according to the calculations of a team of American researchers who published their findings Monday as a discussion paper at IZA-Institute of Labor Economics, based in Germany.
Using cellphone data, researchers ranked Spokane County as one of many “high inflow” counties, in terms of sending people to the rally. High-inflow counties, on average, showed an increase of 10.7% in cases two weeks after the event ended, over what they would have otherwise expected.
The overall cost of cases resulting from the Sturgis virus party was estimated at more than $12 billion.
“Taken together, the results … provide strong evidence that the Sturgis Rally appears to have been a superspreader event for COVID-19; we find significant case increases within the state of South Dakota as well as increases extending to counties from which relatively more residents attended the event,” the researchers concluded.
That’s the bad news. In a pandemic, irresponsibility spreads even to the responsible.
The good news is that in counties with strict public health measures – like ours – the impact back home was probably mitigated.
Their study, “The Contagion Externality of a Superspreading Event: The Sturgis Rally and COVID-19,” was released Monday.
The figures in the research are estimates based on cellphone tracking data, federal case counts and modeling. In Spokane, during the period in which the average case loads were rising in the high- attendance counties, our case numbers were fluctuating around the 40-per-day level, where they have been for a few weeks.
Dr. Bob Lutz, our county health officer, said he was aware of three cases in Spokane County that originated in Sturgis. However, during the period after the rally when cases would have been showing up, the state was handling much of the testing and tracing activity, and would not have necessarily been checking for connections to the rally, he said.
It is not surprising that the Sturgis rally produced a lot of new infections, at least if you have followed the factual landscape of the pandemic. There is now a lockstep relationship between examples of people dropping their guard and the resulting rise in case numbers. But measuring the actual results of a superspreader event has been difficult before now, given that large gatherings have been banned all over the country.
Sturgis provided one hell of a real-life sample. Unlike almost every other event in the country, rally organizers pressed ahead against the guidance of the federal government and health officials. South Dakota’s lack of an outright ban on large gatherings left local leaders with little recourse but to try, by encouraging masking and social distancing, to make it as safe as possible.
Around 460,000 people traveled to the town of roughly 7,000. There were dozens of concerts, races, bike shows and other events, along with lots of drinking and partying.
“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,” the authors wrote.
Researchers estimated which counties sent the most people to the rally based on tracking cell-phone pings – Spokane was one of the biggest, along with larger counties in Arizona, California, Colorado, Iowa, Minnesota, Nebraska, Nevada and Wyoming.
They also used cellphone data to estimate how frequently locals in Sturgis went out to public places, and found they were doing so much more than usual.
They then examined case counts, and found strong correlations between the rally and a subsequent rise in cases. They found it in Meade County, where Sturgis is located. They found it in the immediately surrounding counties. And they found it everywhere that large numbers of people returned home, where it could spread in a whole new community.
It’s just one more object lesson in the reasons to be careful as the pandemic drags on. Even if you’re not moved by the potential downstream health effects, consider that the average cost of one COVID-19 case is $46,000, to individuals and the health care system, according to the researchers.
Their estimate of a $12.2 billion financial impact of COVID-19 cases arising from the Sturgis rally might give even the staunchest virus scoffer pause:
“This is enough to have paid each of the estimated 462,182 rally attendees $26,553.64 not to attend.”
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