A new CDC report has detailed how a 47 person Covid-19 outbreak in Oklahoma in spring was caused by the Delta SARS-CoV2 variant. The outbreak took place at a gymnastics facility and affected 23 gymnasts, 3 staff members, and 21 of their household contacts with the age range of infected people being between 5 and 58 years old.
Forty people involved in the outbreak (85%) had received no vaccination against Covid-19, three had received 1 dose of an mRNA vaccine and four people were fully vaccinated with either two doses of an mRNA vaccine or a single dose of Johnson & Johnson’s vaccine. All vaccinated people with Covid-19 were reported to be mildly symptomatic, but two unvaccinated adults with Covid-19 in the outbreak were hospitalized and one required intensive care treatment.
Of the 47 affected people, 21 samples were available for DNA sequencing to identify the precise variant involved. All 21 of these were identified as the Delta variant. At this time in Oklahoma, the facility was permitted to operate under several guidelines designed to reduce the risk of transmission. However, upon interviewing people involved in the outbreak and visiting the gymnastics facility, CDC representatives noted several breaches of recommended guidelines which may have contributed to worsening the outbreak. These included non adherence to quarantine and testing guidelines, ignoring infections and not wearing masks while in the facility but not actively participating in sport. The facility was also found to have poor vaccination and inadequate cleaning of high-touch surfaces after use.
“These findings suggest that the B.1.617.2 variant is highly transmissible in indoor sports settings and households, which might lead to higher attack rates among exposed persons,” – CDC report on Oklahoma gymnastics facility outbreak.
Ten of 16 training cohorts at the facility were affected and the report found that 20% of exposed people at the facility contracted Covid-19 during the outbreak. The report authors suggest that the outbreak demonstrates that the variant is easily transmissible in high-risk environments, especially where disease control guidelines are not being properly followed.