November 14, 2022 | Erin Bluvas, bluvase@sc.edu
Throughout the pandemic, researchers from the Departments of Environmental Health Sciences and Epidemiology and Biostatistics have worked with Student Housing and Sustainability to monitor levels of the SARS-CoV-2 virus that causes COVID-19 in wastewater across campus. Within months of the pandemic’s onset in the United States, they were even partnering with treatment plants in different communities (eight across SC and others in Texas and California).
While refining and expanding their programs, methods and analyses over the past two years, the team discovered that building-level surveillance (e.g., monitoring virus levels in the wastewater of a particular building rather than solely at the community level) provides additional useful information, including the emergence of variants and the presence of viral transmission hotspots. They published their findings in Environmental Research as part of the Elsevier Public Health Emergency Collection.
“Building-level wastewater surveillance of SARS-CoV-2 provides an in-depth analysis of sub-community transmissions, especially in high-density facilities,” says Sean Norman, associate professor of environmental health sciences and the lead researcher on USC's wastewater surveillance initiatives. “While community-level wastewater monitoring gives us an understanding of what is currently happening in terms of viral transmission, there are many variables, such as the dilution or mixing of wastewater from multiple sources, that interfere with our ability to accurately measure viral levels and can ultimately mask new variants and hotspots.
Known to scientists as “wastewater epidemiology,” Norman had already received funding from the Centers for Disease Control in Prevention in 2018 to advance this emerging field by monitoring levels of antibiotic resistant bacteria in environmental reservoirs. Two years later, he lent his expertise to the COVID-19 response, making USC one of the first universities to complement clinical testing with both community- and building-level surveillance when the campus reopened.
As part of this monitoring, the team collected two 24-hour wastewater samples per week during the 2021 spring semester from 10 residence halls as well as the on-campus student isolation and quarantine building, which served as a positive control site. Examining this data, the researchers identified the early presence of the Alpha variant, which later contributed to the second wave of COVID-19 cases. They were also able to detect transmission hotspots, allowing for targeted interventions in real time.
“Passive surveillance allows for large communities to be monitored without wasting resources or burdening the general public and can predict increased transmission earlier than clinical testing-based methods,” Norman says. “Having seen the widespread benefits of wastewater surveillance, it is likely that these systems will be adapted for the detection of seasonal viruses and future emerging pathogens as a mitigation tool to prevent outbreaks, decrease health care costs and save lives.”
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Coronavirus in wastewater treatment plants potential pathway to population testing