Symptomatic SARS-CoV-2 Transmission in Youth and Staff Attending Day Camps

Consistent with the CDC guidelines for congregate care settings, the YMCA followed locally mandated SARS-CoV-2 mitigation recommendations for children attending day camps.¹⁰  These mitigation protocols included exposures and symptoms screening, daily temperature checks, masks for all staff and attendees, frequent hand hygiene (hand-washing indoors and hand sanitizer in outdoor settings), physical distancing (>6 ft), small cohorts (≤10 youth and 1 adult), scheduled site cleanings, and staff COVID-19 education and workplace training.¹⁰  Specifically, participants’ parents and/or guardians and staff were asked to immediately report COVID-19 symptoms or diagnosis to the YMCA. Intake staff took an initial report shared with direct supervisors and the Risk Department to determine recommended quarantine or isolation duration per CDC guidelines. For all reported cases, the Risk Department alerted Human Resources, Communications, and Facilities to trigger planned responses, including tracing potential contacts in collaboration with local health departments and performing enhanced cleaning of facilities where the infected camper or staff was present. If individuals became symptomatic at home, strict protocols were followed, per CDC guidelines, before permitting on-site return. If a child became ill with symptoms while in attendance at camp, personal protective equipment (gloves and surgical facemasks) was used to care for the child.

During camp, universal mask wearing was enforced by staff for all indoor activities (including contact sports), and also for outdoor activity if participants were unable to remain physically distanced (6 ft or more). Youth were required to wear masks when getting out of a car during drop off and were reminded to keep masks on at all times. Mask wearing was prioritized by YMCA administrators and staff on the basis of advice from a medical expert advisory panel assembled early in the pandemic. Per internal audit, in accordance with the state mandate issued on June 24, 2020,¹⁴  there was >95% mask compliance among campers and staff. Youth and staff cohorts were maintained such that there were ≤2 consistent exposure groups that each included up to 10 youth and 1 staff (total 22 individuals) permitted to play together but also to avoid contact with other groups. No large group engagements were permitted per NC state governor mandate issued on March 14, 2020.¹⁵ 

All participant and staff data including participant and staff demographics, enrollment and work assignments, attendance, number of positive SARS-CoV-2 testing with linked symptom onset dates, close contacts, cleaning and disinfecting response, and contact with the health department were collected by the YMCA, deidentified, and shared with Duke University through a data use agreement. This study was approved by the Duke Health Institutional Review Board (Pro00106484).

Deidentified data for symptom screening and self-reported cases were retrospectively obtained from the YMCA prospectively collected database. Data were included for youth and staff who attended or were staffed at YMCA youth indoor, outdoor, and split indoor and outdoor camps (n = 54) in 6 NC counties (Chatham, Durham, Johnston, Lee, Orange, and Wake) during the study period (March 30 to August 24, 2020). Any youth who attended YMCA camps during the study period from March to August were captured for the period that they attended camp by the YMCA’s data tracking tool. Campers and staff attended or were assigned to only 1 camp session per week. Contacts were defined as any youth or staff present in-person on campsite during the week before identification of positive case.

Descriptive statistics were computed to summarize sample characteristics across age, race, and sex for youth and staff. Camp characteristics (number of youth and staff, sites, and camps) were also computed. Means and SDs were generated for age of youth and staff, attendance (percentage of days attended/total days eligible to attend based on camp duration) and camp duration (total days) overall, and camp location (primarily indoor, primarily outdoor, and split indoor and outdoor).

Next, primary campsite attack rate and campsite-related secondary case transmission rate were calculated. Calculations accounted for all campers and staff who were present on-site at the same camp during the study period. Primary cases were defined as index youth or staff reporting COVID-19 infection without any known exposure at camp; secondary cases were defined as cases from potential exposures within camp. A symptomatic SARS-CoV-2 case was defined as a self-reported (camper or staff) positive viral SARS-CoV-2 polymerase chain reaction test from a specimen collected or reported to the health department or other testing center. A contact was defined as any individual who had close contact (<6 ft for 15 minutes or more) on-site with primary cases during camp week of infection with or without masks in accordance with local and state health department policies.¹⁶  Primary case attack rate was calculated as the number of new primary cases during the camp week of infection/number of participants on-site at the same camp during the week of infection. Secondary case transmission rate was calculated as the number of symptomatic secondary cases among contacts of primary cases/(number of contacts − number of primary cases). Statistical analyses were performed by using SAS v.9.4 (SAS Institute, Inc, Cary, NC).

Youth were 66% white, 54% male, and had a mean age of 8.5 years, with mean attendance rate of 88% (n = 5344). Staff were 64% white, 60% female, and had a mean age of 22 years (n = 1486, Table 1). Twenty-nine (54%) camps were primarily outdoors. Thirty-nine percent and 38% of youth attended indoor and outdoor camps, respectively, whereas 23% of youth attended split indoor and outdoor camps. The percentage of all youth identifying as racial or ethnic minorities by camp setting was 23% and 25% for indoor and split indoor and outdoor camps, respectively, compared with 18% for outdoor camps. Mean camp cohort size and duration were 20 youth, 6 staff, and 5 total days (typically 7:30 am to 6 pm). Staff completion rate for 3 COVID-19 virtual training sessions before the beginning of camp was 67%. Seventeen primary symptomatic SARS-CoV-2 infections occurred during the study period among 9 youth (mean age 9.7 years) and 8 staff (mean age 27 years, Table 2) who were linked to 3030 contacts present in person during the week before positive cases and only 2 symptomatic secondary infections (1 youth and 1 staff) linked to primary cases. Symptomatic SARS-CoV-2 primary case attack rate was 0.6% (17 of 3030), and secondary case transmission rate was 0.07% (2 of 3011). The most common reported symptoms (for youth and staff combined) were fever (55%) and cough (45%). No hospitalizations were reported. Attack rates per campsite can be found in Supplemental Table 3. Moreover, no COVID-19 case clusters (locally defined as <5 related cases) occurred in these camps.¹⁷ 

Extremely low youth and staff symptomatic SARS-CoV-2 attack and transmission rates were observed during a 147-day period across 54 YMCA camps from March to August 2020, a period when COVID-19 prevalence in NC was at its first peak.⁴  Comparatively, during this period, COVID-19 incidence rate in NC was 200 new cases per 10 000 population per day.⁴  Low symptomatic SARS-CoV-2 attack and transmission rates also contrast with previous reports for youth ages 6 to 19 who attended an overnight camp in Georgia, where a 44% attack rate also based on symptomatic testing was reported.¹³  However, differences in mitigation practices were reported between the overnight camp in Georgia and the YMCA camps, including in the Georgia camp a lack of adherence to both masking practices and physical distancing, indoor singing or shouting while unmasked, and reliance on tests within 12 days of camp (versus days before infection to avoid re-exposure).¹³  Instead, our findings correspond to data from other reports of congregate care settings based on symptomatic testing of contacts, including Rhode Island child care programs (median age 5 years), indicating limited secondary transmission of SARS-CoV-2 in congregate care settings with adherence to mitigation protocols.¹²  Similarly, some reports have revealed that transmission among youth returning to schools after reopening has been low,^18,19  and outbreaks in these settings have been attributed to lack of adherence to both masking and physical distancing,^20,21  suggesting that reinforcing mitigation strategies with youth and families is imperative. Future work should identify SARS-CoV-2 screening and education protocols for promoting adherence to guidelines in congregate care settings to allow children, particularly those from vulnerable groups, to safely return to school, child care, and recreation settings.

Importantly, during a period of rapid regional increase in SARS-CoV-2 incidence rates, there were only 19 COVID-19 cases among 6830 youth and staff. The majority of participant and staff cases were primary cases, likely reflecting community or household transmission. Also, although minority youth were more likely to attend indoor camps (where expected transmission risks may be increased), we did not observe higher transmission rates in these settings. This finding may be particularly relevant to school and other congregate care settings where the majority of time has to be spent indoors because of weather or learning conditions.

It may be hypothesized that basic infection control protocols including masking, hand-washing, physical distancing, thorough staff training, and organizational resources dedicated to COVID-19 mitigation successfully reduced transmission within recreation settings for children. Additionally, the near absence of secondary transmission within YMCA camps may have been due to judicious application of public health guidance, small-sized cohorts, and emphasis of safe practices for both youth and staff in and out of camp. YMCA allocated resources to detailed contact tracing, audited COVID-19 mitigation protocol adherence, and accessed advice from a medical board with pediatrics, epidemiology, and infectious diseases expertise, all of which may have contributed to the limited on-site transmission.

Study limitations include potential underestimated attack and transmission rates due to missed asymptomatic cases, reliance on a convenience sample with self-report for identifying positive cases, and limited reporting on staff compliance with trainings because of technology limitations. However, authors of previous reports of SARS-CoV-2 transmission in congregate care settings similarly drew from self-report data and convenience samples.^12,13  The state of testing that was available in the first 6 to 8 months of the pandemic, which this report covers, included very limited asymptomatic, standardized, or randomized testing, especially for children; therefore, prospective testing was not available at YMCA camps. Data confirming daily mask wearing and distancing compliance were not available.

Despite these limitations, this work reveals that SARS-CoV-2 transmission can be mitigated in congregate care settings during times of high community incidence, suggesting that the benefit of in-person programming for supporting youth learning, mental health, and school retention, particularly for vulnerable populations, outweighs the risk of viral spread. There are few formal data on transmission of SARS-CoV-2 in school, child care, and recreation settings. Thus, these data reflect an important contribution for school systems and child care settings as they navigate this exceedingly difficult time to promote the wellbeing of children and primary caregivers. Future research should address feasible and effective COVID-19 protocols in school, child care, and recreation settings, particularly among disproportionately affected racial and ethnic groups, to inform best practices for reducing immediate and long-term impacts of COVID-19 on youth and their families.

We thank Charlene Wong, Jillian Hurst, Katherine Barrett, Doug McMillan, Kim Keith, Leah Devlin, Anna Goodmon, Kirk Newman, Sallie Ransom, and John Rusher for their valued insight, which informed the preparation of this manuscript.

COVID-19

Coronavirus Disease 2019

NC

North Carolina

SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2

YMCA

YMCA of the Triangle