Performance and suitability of wastewater based-surveillance for SARS-CoV-2 RNA in public schools

Wastewater-based surveillance (WBS) for SARS-CoV-2 was a key strategy for epidemiological modelling and informing COVID-19 health policy during the pandemic. We assessed the capacity and performance of SARS-CoV-2 WBS in public schools. Of seventeen schools screened for participation, only four had plumbing systems that were amenable to comprehensive monitoring. From December 2020 to March 2021 composite wastewater collected twice-weekly from these four schools was compared with three municipal wastewater treatment plants (WWTPs) for SARS-CoV-2 RNA by RTqPCR and fecal biomarkers. Schools had lower rates of successful sample collection relative to WWTPs (64/79 vs. 66/66, p < 0.001). In a time of low COVID-19 activity, 13/64 of school samples were positive for SARS-CoV-2, versus 66/66 for WWTP (p < 0.0001). SARS-CoV-2 RNA in school wastewater was associated with, and often preceded, clinically confirmed COVID-19 cases among students, but showed no correlation with overall rates of student absenteeism. Levels of both SARS-CoV-2 RNA and fecal biomarkers were markedly lower in school wastewater relative to WWTPs. This work demonstrated that WBS for SARS-CoV-2 in schools can be a leading indicator of clinical disease but is technically challenging. The lower fecal biomarker levels from schools suggests children may avoid defecation at school which may further adversely impact school-based WBS for fecal-shed targets.