What Does Chicagoans' Poop Tell Us About Coronavirus Case Spread?

CHICAGO — From funny greeting cards to gag gifts — like the illustrated "What's Your Poo Telling You?" bathroom book I got for my birthday — crappy jokes about feces and farts are family favorites.

But the public health department's recently released study of coronavirus in city wastewater is serious business.

Wastewater surveillance can be used to track the spread of coronavirus because the virus is shed in feces regardless of a person's symptoms or the results of diagnostic testing, public health officials say.

Tracking the presence of the COVID-19 virus in sewage treatment plants that take in wastewater from millions of toilets at once offers a good "overview" of how prevalent the virus is in different parts of town.

In December, for instance, an analysis of turds flushed in my part of town that made their way to the Calumet Water Reclamation Plant, on the far South Side, showed the city's highest spike in coronavirus the second week of December.

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That increase coincided with the start of the latest COVID-19 surge in cases confirmed by reported cases, test positivity rates and hospitalizations.

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On Dec. 12, the omicron variant was detected in wastewater samples, less than a week after Chicago reported its first case and before the COVID-19 variant was the dominant cause of illness here.

The information from poop-related surveillance helps public health officials better understand how the virus is spreading in different parts of town.

In December, the city health department tracked the swiftly increasing prevalence of coronavirus by collecting sewage catch basin samples twice a week in seven neighborhoods designated as health-equity zones.

Public health officials use the turd-derived data to determine where to push increased coronavirus testing and efforts to boost vaccinations.

More information on what poop can tell you about the state of coronavirus spread in your neighborhood is available online.

It's sounds like a poop joke, but it's not.