More than 330 coronavirus cases and one death were directly linked to the rally as of mid-September, according to a Washington Post survey of health departments in 23 states that provided information.
That number likely represents just the tip of the iceberg, according to experts.
Contact tracing often doesn’t capture the source of infection, and asymptomatic spread goes unnoticed.
Within weeks of the Sturgis rally, South Dakota, North Dakota, Wyoming, Minnesota, and Montana were leading the surge in new coronavirus cases.
The Dakotas saw case numbers and rates of hospitalisation rise enormously throughout September, and into October.
It may never be confirmed how many cases stemmed