'Cautiously optimistic': Declining COVID-19 levels in wastewater show promising signs

NOW: ’Cautiously optimistic’: Declining COVID-19 levels in wastewater show promising signs

MADISON, Wis. (CBS 58) -- The surge of new COVID-19 infections may have turned a corner, according to researchers who track sewage.

New data from the Department of Health Services show COVID-19 levels in Milwaukee's wastewater are dropping to where they were in late December, before cases started to spike dramatically.

Experts in wastewater say it's a sign that the surge could be nearing an end.

Trina McMahon is a professor of engineering and bacteriology at UW-Madison and said wastewater is a leading indicator to see how prevalent COVID-19 is spreading in communities.  

"I would predict in the next week or two we'll see a clear signal of it going down in Wisconsin," said McMahon.

Levels of COVID-19 material in wastewater typically coincide with case totals from the state, which are also declining.

With more people now testing for the virus at home, researchers say wastewater is key, because it can also track asymptomatic people and new variants.

"As home tests become more and more popular, that data is going to be lost in trying to track community, but wastewater does not depend on people deciding to get a test or having symptoms," said Sandra McLellan, professor at UW-Milwaukee School of Freshwater Sciences.

Researchers at UWM have been tracking wastewater from sewage facilities across the state for about two years.

McLellan also predicts Wisconsin's omicron cases will peak very soon, but also cautioned it might be too early to tell.

"We're cautiously optimistic that we hope we're nearing the peak," McLellan said. "Wastewater data is literally a half-million people being sampled in a single bottle, so we have to think about how that can vary and we want to see a trend after 2-3 weeks' time."

McLellan also said UWM's School of Freshwater Sciences is expected to start tracking the flu and other viruses by using wastewater monitoring.

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