A new study reports that the Sturgis Motorcycle Rally may be linked to more than 250,000 COVID-19 cases across the country, but South Dakota health officials countered that the study has yet to be peer-reviewed, and Gov. Kristi Noem said the study is “grossly misleading” and built on “incredibly faulty assumptions that do not reflect the actual facts and data here in South Dakota.”
“This report isn’t science; it’s fiction,” Noem said. “Under the guise of academic research, this report is nothing short of an attack on those who exercised their personal freedom to attend Sturgis.”
Researchers from the Center for Health Economics and Policy Studies at San Diego State University attributed more than 250,000 coronavirus cases to the event by reviewing anonymized cellphone data. They also estimated the rally generated $12.2 billion in public health costs.
The study also concluded that counties outside of South Dakota that sent the highest proportion of residents to the rally — including Natrona and Campbell counties in Wyoming — experienced a 10.7% increase in coronavirus cases about two weeks after the rally ended.
South Dakota Department of Health officials said Monday that they had seen the study, but that they would dispute several data points, such as the projection of hundreds of thousands of cases and the basis of using cellphone data to track the spread of COVID-19.
State epidemiologist Joshua Clayton said it’s important to note that the study is a “white paper” study and hasn’t been peer-reviewed and that it doesn’t account for “an already increasing trend of cases” in South Dakota and the timing of schools and colleges reopening.
“The results do not align with what we know for the impacts of the rally among attendees in the state,” Clayton said.
State health secretary Kim Malsam-Rysdon said Tuesday that she would caution reporters against “putting too much stock into models” and pointed to earlier estimates by the state that as many as 600,000 South Dakotans would get COVID-19.
“There was a point when we thought we would see many, many more infections of COVID-19 in our own state, with or without the rally at a time in the past,” she said. “Whether it’s the potential impact of the Sturgis Rally or other models that can’t be verified by other factual numbers, that is the case of this particular white paper.”
Clayton said 124 state residents had attended the Sturgis Motorcycle Rally prior to becoming ill, but the health department isn’t including secondary infections in that tally. A secondary infection would be someone who went to the rally, contracted COVID-19 and then infected a friend or family member who was not at the rally.
Malsam-Rysdon said the DOH has the ability to investigate all cases and identify close contacts, which is the “best way to track secondary infections,” but that community spread in the state and country makes it harder to track the sole source of an individual’s illness.
“We’ve got more people that are becoming sick with COVID-19 from a source that we can’t identify, so I think that’s where it gets problematic to just attribute things like cellphone data” as the source of infections, Malsam-Rysdon said.
Both Malsam-Rysdon and Clayton said they knew cellphone pings from residents of other states and foot traffic increased during the rally, but that they haven’t seen cellphone traffic as a “proven link” to COVID-19 infections or spread.
Clayton said he’s not familiar with the cellphone data source used in the study and what the limitations are for that data.
When asked if a national contact tracing plan could help in determining the full scope of COVID-19 cases relating back to the Sturgis Motorcycle Rally, Clayton said the CDC is in the process of evaluating a call for cases that tie back to the rally to collect data on the event.
“We will participate if that does come to a true call to states to submit those cases,” Clayton said.
Clayton said the DOH has been consistent in sharing Centers for Disease Control and Prevention recommendations against attending large events like the Sturgis Motorcycle Rally and that the risk of COVID-19 spread can increase with the size of the gathering.
Concerned about COVID-19?
Sign up now to get the most recent coronavirus headlines and other important local and national news sent to your email inbox daily.