Nineteen percent of the 1.4 million new coronavirus cases in the U.S. between Aug. 2 and Sept. 2 can be traced back to the Sturgis Motorcycle Rally held in South Dakota, according to researchers from San Diego State University's Center for Health Economics & Policy Studies.
That's more than 266,000 coronavirus cases attributed to the 10-day event, which more than 460,000 people attended despite fears it could become a so-called super-spreader event.
"We conclude that the Sturgis Motorcycle Rally generated public health costs of approximately $12.2 billion," the researchers wrote in a paper. "This is enough to have paid each of the estimated 462,182 rally attendees $26,553.64 not to attend."
The event took place from Aug. 7 to Aug. 16 in the town of Sturgis, which has a population of roughly 7,000 people.
The researchers said the rally increased coronavirus cases by approximately six to seven per 1,000 population in Meade County, home to Sturgis.
"These results suggest that in contrast to prior large gatherings that have been studied (i.e., Tulsa and BLM protests), in the case of Sturgis, the local resident population appeared to participate in the events," the researchers wrote. "This raises the possibility that the local population may be at risk for COVID-19 spread, especially if mitigating strategies (i.e., mask-wearing, interacting closely with only household members, avoiding crowds) were not undertaken."
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In this Aug. 7, 2020, file photo, people congregate at One-Eyed Jack’s Saloon during the 80th annual Sturgis Motorcycle Rally in Sturgis, S.D. (AP Photo/Stephen Groves File)
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People crowded around bars in Sturgis, S.D., on Friday, Aug. 7, 2020, during the 80th anniversary of the Sturgis Motorcycle Rally. (AP Photo/Stephen Groves)
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Bikers walk down Main Street during the 80th annual Sturgis Motorcycle Rally on Saturday, Aug. 15, 2020, in Sturgis, S.D. (Amy Harris/Invision/AP)
Researchers from the Center for Health Economics & Policy Studies also studied the spread of COVID-19 tied to Black Lives Matter protests throughout the U.S. and concluded the protests did not have as harmful an effect on public health as some feared.
"We conclude that predictions of population-level spikes in COVID-19 cases from Black Lives Matter protests were too narrowly conceived because of failure to account for non-participants' behavioral responses to large gatherings," the researchers wrote in a paper originally published in June.
Photographs show attendees largely ignored social distancing guidelines and seldom wore masks. They packed bars and local businesses, and stood shoulder-to-shoulder at live music performances.
South Dakota Gov. Kristi Noem never issued a shelter-in-place order for her state.
"I trusted my people, they trusted me to make decisions that were best for us, and they’ve just done an absolute fantastic job," Noem told "Hannity" in April. "That’s why my plan is not a reopening plan, it’s a back-to-normal plan."
Fox News' Michael Ruiz and The Associated Press contributed to this report.