Thirteen festivalgoers and four staff members have been diagnosed with COVID-19 after attending Country Jam in Mack, Colo., in late June. The area was a hotspot for the Delta variant of the virus prior to the festival, and officials worry the three-day event could have accelerated the spread.

A list of 50 new (since early June) and active outbreaks identified by the Colorado Department of Public Health and Environment was published by Westword, an independent newspaper in Denver. Of the 50, the Country Jam outbreak was the second-largest. Reporting by the Denver Post reveals that Mesa County, in which Mack is located, has more Delta variant cases than any county in Colorado. State epidemiologists and the Center for Disease Control were on site prior to the festival to investigate the cause.

Furthermore, Colorado has one of the highest proportions of the Delta variant among all 50 states. The paper reports that 42 percent of vaccine-eligible adults have gotten the shot. Grand Junction's Daily Sentinel reported crowds of up to 24,000 each night during Country Jam, where Luke Combs, Toby Keith and Carrie Underwood were headliners.

The number of cases that were of the Delta variant, and the number of hospitalizations in total, has not been shared by health officials. There were signs asking patrons to wear a mask, but it wasn't required. There was also a mobile vaccine clinic that the Denver Post reports was empty when they visited.

At one point prior to the festival, health officials considered canceling the event, but decided it was too late. An announcement reaffirming the fest would happen led to the sale of 23,000 tickets.

Country Jam Colorado was formerly owned by The Boot's parent company, Townsquare Media. Festival organizers have yet to comment on the outbreak.

Enter your number to get our free mobile app

Top Country Songs of 2021, Ranked

You'll find much more than just the Top 10 Country Songs of 2021 on this list.

Our team has sourced fans to create 10 superlatives for this mid-year version of the year-end songs list. Best Country Tearjerker? Best Country Baby-Maker? Best Country Breakup Song of 2021? Keith Urban, Carly Pearce, Chris Bandi and more help make up this portion of the Top Country Songs list while hitmakers like Thomas Rhett and Little Big Town lead the 10 best songs portion.

Did your favorite song of 2021 make this list? To be considered, the song must have been released in 2021 or have actively charted for a portion of the year (see "Wine, Beer, Whiskey"). New artists includiong Lainey Wilson, Breland and Triston Marez crack the Top 10. Let us know your favorite song of 2021 at Twitter or email, at staff@tasteofcountry.com.