Georgia youth summer camp had major outbreak of COVID-19 with 76% of testees positive: MMWR

The Morbidity and Mortality Weekly Report (MMWR) for July 31 had this: A summer camp attended by children and teenagers aged 6-19 was affected by an outbreak of COVID-19. There was an overall “attack rate” of 44% (260 of 597) but only 58% were tested… 76% (260/344) of those tested had positive results for SARS-COV-2 antigens. 27 attendees were excluded from analysis because they were from out of state.

The camp was in Georgia, and was said to have required a negative test within 12 days before attendance. Staff members (120 people aged 14-59) were required to wear masks but the attendees were not. The session began with training held June 17-20, followed by camp starting June 21 and scheduled to end on June 27. On June 23, a staff member developed symptoms (chills) and left; the positive test was reported the next day and the camp was emptied out. The Georgia Department of Health began an investigation on June 25.

Here is a quote from the MMWR report:

A total of 597 Georgia residents attended camp A. Median camper age was 12 years (range = 6–19 years), and 53% (182 of 346) were female. The median age of staff members and trainees was 17 years (range = 14–59 years), and 59% (148 of 251) were female. Test results were available for 344 (58%) attendees; among these, 260 (76%) were positive. The overall attack rate was 44% (260 of 597), 51% among those aged 6–10 years, 44% among those aged 11–17 years, and 33% among those aged 18–21 years (Table). Attack rates increased with increasing length of time spent at the camp, with staff members having the highest attack rate (56%). During June 21–27, occupancy of the 31 cabins averaged 15 persons per cabin (range = 1–26); median cabin attack rate was 50% (range = 22%–70%) among 28 cabins that had one or more cases. Among 136 cases with available symptom data, 36 (26%) patients reported no symptoms; among 100 (74%) who reported symptoms, those most commonly reported were subjective or documented fever (65%), headache (61%), and sore throat (46%).

Szablewski CM, Chang KT, Brown MM, et al. SARS-CoV-2 Transmission and Infection Among Attendees of an Overnight Camp — Georgia, June 2020. MMWR Morb Mortal Wkly Rep. ePub: 31 July 2020. DOI: http://dx.doi.org/10.15585/mmwr.mm6931e1

This summer camp, apparently a typical one, lasted only two days out of a planned seven, after a staff member developed symptoms and was sent home. It was too late by then to prevent 76% of those tested from developing COVID-19 in the two weeks after they went home.

The only unusual feature of this outbreak was that 74% of the positive cases had symptoms– mostly fever, headache, and sore throat. Note that the “attack rate” was highest among the youngest attendees.

What can I say that hasn’t already been said? Maybe wearing masks would have helped? Maybe group sing-alongs and cheering was a bad idea?

It is possible, indeed likely, that the first patient with symptoms was infected just prior to arrival at the camp, since it appears from the timeline that they arrived June 17 and symptoms started June 23. Having a negative test up to 12 days before arrival would not have been sufficient to prevent this occurrence.