South Dakota hosted a 10-day Motorcycle rally hosting approximately 400,000 people. Weeks later, a list of 250.000 COVID deaths, now linked to it. Studied by IZA Institute of Labor Economics, the event hosted in August drew more than 250,000 cases.
Researchers from:
- University of Colorado Denver
- Bently University
- University of California San Diego
- San Diego State University found the bikers.
The search carried out through anonymised cellphone data from the rally. The bikers were filmed and photographed in crowded bars, restaurants and outdoor venues were mostly without face masks. It allowed for many of the worst-case scenarios of superspreading.

The prolonged event increased spread probability. It included individuals packed closely together and involved a sizeable out-of-town population. They had low compliance with recommended infection countermeasures such as the use of masks, the researchers wrote.

The estimated cost of the event stood around $12.2 Billion in Health Care costs.
Foot traffic at restaurants, bars, hotels and shops in census block groups where the events took place rose by up to 90% during the event, acc to cellphone data. Simultaneuosly, stay-at-home behaviour declined among residents of Meade County with an up to 10.9% decline in median hours spent at home. Data from the Centers for Disease Control and Prevention found cases spread both locally and in the home counties of those who attended and then travelled home.
The researchers wrote that in the countries with the most massive relative inflow to the event per 1000 case rate increased to a mind-boggling rate of 10.7% after 24 days following the onset of the mentioned bike rally.
Right after multiplying the percentage of increment in cases for the high, moderately high, and moderate inflow of countries by each country’s respective pre-rally cumulative COVID points aggregated. It led to a yield of total 263,708 additional cases in the given location due to the Sturgis Rally.
After the rally, increased cases added to the total tally. Estimated by synthetic control (3.6 per 1000 population)brings the total number of issues to 266,796. It calculated up to 19% of 1.4 million new cases of COVID-19 in the US between 2nd August to September.
The Cellphone data allegedly recovered from SafeGraph Inc, a San Francisco based data company.