Sewage Could Soon Help Track COVID-19

The research team is part of a preliminary statewide monitoring effort with 15 wastewater treatment plants and recently began analyzing Notre Dame’s wastewater. (Courtesy: Pixabay)

That which makes most wrinkle their noses could help crack the code in how to monitor COVID-19. A University of Notre Dame scientist is contributing to local and worldwide efforts to use wastewater, or sewage, as a tool to monitor SARS-CoV-2, the virus that causes COVID-19. Far less expensive and more streamlined than testing individual people, the method is gaining traction; 15 wastewater treatment plants in Indiana are already helping tweak the technique.

Notre Dame Associate Professor and Civil and Environmental Engineering and Earth Sciences Wanzek Collegiate Chair Dr. Kyle Bibby is spearheading the research. His studies focus on viral RNA in wastewater. Most people infected with SARS-CoV-2 excrete the viral RNA in their stool, which can then be detected in wastewater. Bibby emphasizes this viral RNA is only a “signal,” not an infectious pathogen that could find its way into tap water.

“The general idea is because people excrete the signal of the virus, we can measure it in the wastewater,” says Bibby, “and some research has shown that gives us an early detection or early warning of increases in the community.”

It isn’t a new strategy; the method has been used for decades to monitor other viruses—most notably, polio, which is tracked by various monitoring networks that rely on wastewater in places where the virus is endemic.

Bibby says there are three potential applications for monitoring the SARS-CoV-2 signal in wastewater. The first is surveillance: identifying if the virus is present in a community or even at a single location, such as a nursing home, cruise ship or correctional facility, for example. Another application is trend analysis; Bibby says research suggests an increase of the viral signal in wastewater may precede increases in clinical cases by as much as a week, “which would be a pretty notable advance warning of [COVID-19] coming on.” Bibby believes these two applications are close to be implemented.

Finally, wastewater could indicate how many people within the community are infected, but Bibby cautions this use is the furthest away from application and still needs more research.

“[Tracking the coronavirus in wastewater] is very attractive in its apparent simplicity; it’s addressing a problem that’s critical to every aspect of our lives right now,” says Bibby. “But I do think there are some critical technical challenges that need to be solved before we really use this as a widespread management tool. It has a lot of potential, but I think a lot of media attention may have oversold where we are today.”

Bibby says one challenge is that the signal is “noisy,” and averaged over time, but researchers are working to “de-noise” that signal, “so we can make decisions closer to real-time.”

“Part of the challenge is the amount of virus an individual sheds varies quite widely. It’s difficult to predict, ‘Does this concentration come from a few individuals shedding a lot of the virus, or from a lot of individuals shedding a little?’” says Bibby. “If we have community restrictions in place, and we see the concentrations in wastewater are quite low, alongside clinical cases, that would strengthen the argument to lift restrictions and open back up. And [vice versa.] That’s how I envision its practical application; not as a sole source or the only piece of information, but as another piece of information when making these complicated decisions.”

Notre Dame is involved in several projects working to fine-tune the various applications. Bibby’s team is part of a preliminary statewide monitoring effort with 15 wastewater treatment plants and recently began analyzing the university’s wastewater, relaying the findings to campus administrators. The researchers are also collaborating on U.S. and international projects to share data, further develop applications and determine the best way to translate data for meaningful decision-making at public health departments, for example.

“From a research perspective, this is not solved,” says Bibby. “We do not have all of the technical details worked out; to the public, that’s more the nitty gritty. To us, it’s a lot of critical challenges to solve to make this a reality. But we’re working to sort out all of those details, and I don’t think we’re that far away.”