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More than 65 colleges or universities in the United States are testing wastewater, often from dormitories, to anticipate and curb the spread of the coronavirus on campuses, NPR reported, including Colorado State University, where wastewater from 17 sites is collected over a 24-hour period three times a week.
“When we see a spike at that dorm, we can quickly roll out clinical tests of those students, identify individuals that are infected, and move them to quarantine locations so we can stop the outbreak from becoming larger rapidly,” Susan De Long, an environmental engineering professor at CSU, told NPR. “It’s allowed us to stay open, with classes face-to-face.”
Wastewater testing doesn’t tell scientists who’s infected, but it narrows down where they live. That’s an important tactic because colleges have become coronavirus hotspots since students returned to campus in August and September.
Scientists have known since the early days of the pandemic that infected people shed the virus through their feces. By monitoring wastewater from a particular building, researchers can determine that somebody using the bathroom in that building has the virus ― possibly before they even show symptoms, NPR said.
NPR said wastewater and sewage testing also has been done at the University Arizona, Colorado College, the Rochester Institute of Technology, and the University of Virginia.
“Other researchers have tested COVID at wastewater treatment plants and then used computer modeling to try to build a big-picture idea of what happened in their community after the fact,” Lisa Colosi-Peterson, an associate professor in the UVA Department of Engineering Systems and Environment, said in a story on the school website. “Getting building-level data in real time is brand new. We are attempting to reduce outbreaks and target them while they are happening
Colosi-Peterson said she was skeptical at first about wastewater testing for COVID but “nearly jumped out of my chair” upon learning about test results in New Haven, Conn., the home of Yale University.
“The study documented a COVID-19 RNA count from a wastewater facility that had been correlated to a specific number of COVID patients,” she said. “The study showed that we could reasonably predict what the patient caseload would be seven days later if we knew the number of viral RNA copies in the wastewater. We never get this kind of correlation!”
The New Haven study, published on the preprint server medRxiv, pointed out that the most common way to track an outbreak is by testing people with symptoms. That’s “a lagging indicator” because people may not show symptoms for days ― if at all.
Sewage testing can show evidence of the coronavirus in a few hours, giving health authorities a jump on tamping down an outbreak, the study said.
“Our study could have substantial policy implications,” the researchers said. “Jurisdictions can use primary sludge SARS-CoV-2 concentrations to preempt community outbreak dynamics or provide an additional basis for easing restrictions, especially when there are limitations in clinical testing. Raw wastewater and sludge-based surveillance is particularly useful for low and middle-income countries where clinical testing capacity is limited.”
NPR. “Colleges Turn to Wastewater Testing in an Effort to Flush Out the Coronavirus”
UVA. “Inside the Science of Testing Wastewater at UVA for Evidence of COVID-19”
medRxiv. “SARS-CoV-2 RNA concentrations in primary municipal sewage sludge as a leading indicator of COVID-19 outbreak dynamics”