2025 No https://doi.org/10.2105/AJPH.2024.307925 Fielding-Miller, Rebecca North America Experimental Observational Students Staff Elementary (K-5) Middle/Jr High (6-8) High School (9-12) Viruses COVID rates Mask wearing Wastewater COVID-19 SARS-CoV-2 Schools This observational study linked masking behaviors to SARS-CoV-2 in wastewater at 10 San Diego elementary schools. A 10% rise in masking corresponded to a 10% drop in viral detection, supporting masking as a school mitigation tool.