July 31 (UPI) -- Nearly half of the children and staff at an overnight camp held in Georgia in June tested positive for COVID-19, according to data released Friday by the U.S. Centers for Disease Control and Prevention.
Of 344 campers and staff members for whom test results were available, 260 -- or 44% -- tested positive for the virus, according to the CDC.
Sixty-nine percent of the positive tests involved children aged 11 to 17, and 20% were reported in children aged 6 to 10, the agency said.
However, testing results were available for only 344 of the 597 campers and staff members who attended, so it is possible more were infected with the virus, CDC researchers said.
The camp was held in compliance with an executive order issued by Georgia governor Brian Kemp that allowed overnight camps to operate beginning May 31, the agency said.
The order required all trainees, staff members and campers to provide proof of a negative COVID-19 test within 12 days of arrival and mandated that all staffers wear face coverings, CDC said.
While "the camp adopted some mitigation steps" for the agency's guidance for youth and summer camps, it did not require campers to wear masks and "camp attendees engaged in a variety of indoor and outdoor activities that included daily vigorous singing and cheering, which might have contributed to transmission," the agency said.
Its research of the outbreak "found efficient spread of the virus among campers and staff while noting key steps to minimize the risk for [COVID-19] introduction and transmission in camps were not strictly followed."
The camp was held from June 17 to 27, including a three-day staff orientation from June 17 to 20, CDC said.
On June 23, a teenage staff member left camp after developing chills the previous evening and tested positive for COVID-19 the next day, the agency said. The camp then began to send attendees home.
More than 75% of the confirmed cases had been residing in "large cabins" shared by up to 26 attendees and staff, CDC said.
Among 136 cases with available symptom data, 26% patients reported no symptoms. For the 100 with symptoms, the most common were fever, 65%; headache, 61%, and sore throat, 46%, the agency said.
"Settings, like multi-day, overnight summer camps, pose a unique challenge when it comes to preventing the spread of infectious diseases, considering the amount of time campers and staff members spend in close proximity," the CDC said.