It’s been a month since the Sturgis Motorcycle Rally drew over 460,000 people without enforcing mask-wearing or social distancing. Now, a newly published study indicates that the event is responsible for over 260,000 new cases of COVID-19.

The 80th installment of the annual motorcycle rally took place Aug. 7-16 in Sturgis, South Dakota at the Buffalo Chip campground. With Smash Mouth and Trapt performances scheduled, the event received criticism over encouraging reckless behavior amid the coronavirus pandemic. 

Read More: The Jelly Belly founder launches a Willy Wonka-like contest for a factory

Fans allegedly sent hate mail to Smash Mouth following their involvement. A video uploaded to Twitter captures frontman Steve Harwell reportedly downplaying the importance of social distancing at the event as he states, “We’re all here together tonight! Fuck that COVID shit!”

Trapt’s performance gave rise to a different controversy when Twitter outed the group for overplaying their turnout. Although the crowd was smaller and less engaged than what Trapt had depicted in their cropped Instagram post, photos from the performance still highlight a shocking lack of precautionary measures. Note, there’s not a mask in sight.

Organizers encouraged attendees to follow CDC guidelines and required that they present masks at entry. However, photos and videos from the event showed general non-compliance. A closer look at the event guidelines reveals that organizers asked attendees wear masks "at their discretion."

Read More: Trapt try to take on Danny Diablo after he sides with Ice-T in Twitter beef

Unsurprisingly, the rally has been confirmed responsible for over 260 cases of COVID-19 across 11 states. Minnesota reported the first death associated with this surge in early September after an attendee in his 60s succumbed to the virus. Epidemiologists point out that the reported figures are likely understated due to participants' resistance to testing and contact tracing. 

Responding to these limitations, IZA formulated a study to analyze the event’s public health impact. Using data from cell phones and the CDC, researchers determined that the event contributed to a 100 to 200% increase in COVID-19 cases in Meade County, where the rally took place. Neighboring counties displayed a 7 to 12.5% increase. 

Read More: MCS, Nada Surf and more honor Adam Schlesinger in a new tribute album 

As if these trends aren’t alarming enough, the study suggests that the event resulted in over 260,000 new cases. This figure accounts for 19% of the 1.4 million cases reported in the U.S. over the past month. Based on the average cost of COVID-19 cases, researchers calculate that this surge represents a public health cost of over $12.2 billion so far. 

You can access the full report by IZA here.