More than 80 confirmed COVID-19 cases in Minnesota were traced to this summer's Sturgis Motorcycle Rally in neighboring South Dakota, the Centers for Disease Control and Prevention said in a new report.
A two-month investigation of the outbreak by the Minnesota Department of Health found 86 cases tied to the August rally, which attracted about 460,000 people from across the United States over 10 days, the report said.
Nearly 60% (51) of the cases were in people who reported attending the rally or who traveled to western South Dakota by motorcycle from Aug. 7 to 16 and who had symptoms onset or a specimen collection before Aug. 30 (within 14 days after the end of the rally).
The other 35 cases were confirmed or likely secondary and tertiary cases among household, social and workplace contacts, and were supported by genomic sequencing, the report said.
Among the cases, four patients were hospitalized, and one person died, the CDC said.
About one-third of Minnesota's 87 counties reported at least one case linked to the rally, the report said, highlighting the "far-reaching effects that gatherings in one area might have on another area."
"The motorcycle rally was held in a neighboring state that did not have policies regarding event size and mask use, underscoring the implications of policies within and across jurisdictions," the CDC said.
"These findings support current recommendations for mask use, physical distancing, reducing the number of attendees at gatherings, isolation for patients with COVID-19, and quarantine for close contacts to slow the spread of SARS-CoV-2," it said. "Furthermore, although these findings did not capture the impact of the motorcycle rally on residents of other states, they demonstrate the rationale for consistent mitigation measures across states."
The Minnesota Department of Health conducted its investigation in August and September, after identifying confirmed COVID-19 cases on Aug. 21 in people who attended the rally. The CDC noted that the findings "represent an underestimate of the motorcycle rally’s impact in Minnesota." In the investigation, 10 patients who attended the rally chose not to reveal close contacts, and not all contacts chose to get tested, it said.
In its own study, the Associated Press found that at least 290 people in 12 states tested positive for the virus after attending the rally.
At the time, health experts feared the Sturgis rally would become a superspreader event, with thousands of people from all over the country attending, and many of the events held indoors.
Earlier this month, Minnesota Gov. Tim Walz criticized South Dakota for hosting the annual rally during the pandemic, calling it "absolutely unnecessary," and wished that Gov. Kristi Noem had canceled it and issued a statewide mask mandate, like Minnesota has, according to the AP.
"And this one's a little bit personal because the governor of South Dakota has taken to traveling to other states and criticizing others -- now at a time when that state's hospital capacity is overwhelmed," Walz said, according to the AP.
South Dakota is one of three states, including North Dakota and Nebraska, reporting over 500 hospitalizations per million people, according to the COVID Tracking Project, as COVID-19 surges in the Midwest.
This week, Walz announced a four-week pause on social activities, in-person dining, sports and fitness establishments in response to rising COVID-19 cases and hospitalizations in Minnesota.
Noem has not issued any restrictions during the pandemic, instead encouraging residents to "exercise personal responsibility and make smart choices."