Visitors to Six Flags St. Louis will once again be required to wear face masks indoors starting Monday after the park’s home county reimposed its mask mandate.

The county’s move was in response to a surge in COVID-19 hospitalizations, which rose to 301 on July 21 —  the highest level since February — thanks to the highly-transmissible Delta variant of the virus that causes COVID-19. The St. Louis Pandemic Task Force said nearly 90 percent of COVID-19 patients in St. Louis hospitals are unvaccinated. 

Six Flags St. Louis had ended its mask mandate in May, along with other COVID-19 safety protocols such as physical distancing and temperature checks. The park continued to recommend that unvaccinated guests wear masks, but did not verify anyone’s vaccination status. 

The county rule tosses the honor system out in favor of making all guests over the age of 5, regardless of vaccination status, wear masks at the park’s indoor locations. 

Six Flags St. Louis followers on Twitter responded mostly with anger, as well as repeating the false claims that wearing a face mask “does nothing anyway” (they do) and baselessly asserting that the move is tantamount to saying that COVID-19 vaccines don’t work, even though the overwhelming majority of hospitalizations and deaths are now occurring in the unvaccinated. 

In fact, a recent study published in the New England Journal of Medicine found that the Pfizer vaccine is 88 percent effective against symptomatic disease caused by the Delta variant. 

Political battles may lead to a quick end to the St. Louis County mask mandate, however. Republicans at the county and state level have come out against the new mask order, with Missouri Attorney General Eric Schmitt promising to file a lawsuit Monday to block both the county from enforcing the restored mandate. 

Other Missouri theme parks have not changed their mask policies. This includes Silver Dollar City in Branson, where cases and hospitalizations have surged, less than 30 percent of the county’s population has been vaccinated, and the local mayor has opposed mask mandates and refused to promote vaccination.

Earlier in July, two theme parks in Los Angeles County, California — Six Flags Magic Mountain and Universal Studios Hollywood — also began requiring guests to wear masks indoors once again due to a new countywide mask order.