The Centers for Disease Control and Prevention has released a new report on a coronavirus outbreak that sickened more than 50 individuals who took in-person classes at a Chicago gym last summer.
According to the report, the Chicago Department of Public Health was notified of a potential COVID-19 outbreak at the facility on Sept. 8. Of 81 individuals who attended in-person classes at the gym between Aug. 24 and Sept. 1, 55 individuals ultimately tested positive for the virus, according to the CDC report.
Among that group of 55 positive COVID results, 24 reported that they had suffered serious symptoms of the virus. Just two of the individuals were hospitalized because of the virus, with one person reporting that they had to spend a total of eight days in an area hospital because of COVID symptoms.
No deaths were reported during the outbreak.
Of those individuals, 78% participated in multiple classes at the gym while potentially infectious. Of that group, 22 individuals attended classes on or after dates where they had begun to experience symptoms of coronavirus.
The CDC says that they interviewed a total of 58 individuals who had participated in the classes during the outbreak. Of those individuals, 44 reported that masks were worn infrequently in the gym, including 32 of the individuals who later tested positive for the virus.
Infrequent mask use was reported more commonly among those individuals who tested positive for COVID than among those who did not.
During the period of time before the outbreak was reported, the facility offered several high-intensity exercise classes daily, according to the CDC. All classes were held with less than 25% of capacity, with mask use, temperature checks and symptom screenings required upon entry to the facility. Patrons also brought their own mats and weights, and were stationed more than six feet apart, according to the report.
Students were allowed to remove their masks while exercising, according to the report, a move that runs contrary to CDC recommendations that all individuals wear masks while working out, even during high-intensity fitness classes.
After receiving their first notification of a positive COVID test, the gym shut down and informed all attendees of possible exposure to the virus.
Among the findings of the CDC and CDPH, the lack of consistent mask wearing among attendees was blamed for the large spread of the virus among students. Participation in classes by students who had already begun to experience symptoms was also noted as a contributing factor to the outbreak.
The authors of the study did caution that there were several factors to keep in mind while evaluating data, including incomplete interview and testing data. Of the patrons of the gym, 10 did not participate in interviews or testing protocols, and of the group of 81 individuals who did participate, 58 provided information on in-class behaviors.
Those numbers both mean that cases may have been undercounted.
Researchers also say that whole-genome sequencing was not performed to assess the similarities of the strains of virus that infected individuals in the classes, meaning that some cases may have stemmed from exposure to other individuals infected with the virus, rather than infected classmates.
A link to the full study can be found on the CDC website.
To avoid potential outbreaks at gyms and health facilities, the CDC recommends that patrons and employees should wear masks, even during high-intensity activities. Social distancing should also be put in place, along with improved ventilation, more stations to wash hands, and policies that require employees and patrons to isolate when experiencing COVID symptoms.