COVID-19 Surveillance Testing in Secondary Schools: Findings and Barriers to Implementation

K-12 schools have shown minimal spread of COVID-19 when mitigation measures are employed. This study sought to determine baseline asymptomatic COVID-19 rates in secondary schools as students returned to full-time in-person learning with universal masking in place and to evaluate the logistical obstacles of implementing surveillance testing.

An observational cohort study lasting 11 weeks during spring 2021 included 2,288 students and staff in Wood County, Wisconsin. SARS-CoV-2 nasal polymerase chain reaction testing was done on consenting students and staff to determine baseline disease burden. Teacher surveys collected data on student masking compliance and classroom distancing. Information about percent positivity, secondary transmission, quarantine and distancing policies, screening participation, costs, and volunteer hour requirements were obtained. Modified quarantine for fully masked in-classroom exposures was evaluated.

Percent positivity averaged 3.0% (0%-16.2% weekly) among students and 1.72% (0%-6.9% weekly) among staff. Two cases of secondary transmission were suspected out of 163 individuals quarantined. An average of 15.6% of the school population consented to participate each week. Minimum classroom distance between students ranged from 2.7 to 5.5 feet. Student masking compliance was greater than 87%. The cost of the program was $106,400 and required approximately 300 volunteer hours. The modified quarantine policy, where students were allowed to continue to attend in-person school after exposure to a case of COVID-19 if the infected and exposed parties were masking, did not result in additional transmission.

In the setting of relatively high student masking compliance and limited distance between students, weekly secondary school screening of students and staff in an area of high community disease spread was found to be low yield, costly, and burdensome for the school district. Surveillance participation was low. A modified quarantine policy was not associated with increased in-school transmission. School funding may be better spent on targeted testing or other school expenses, especially with increasing vaccination rates.