Colorado to test wastewater for signs of COVID-19 outbreaks before symptoms begin

The state health department, two universities and 16 wastewater services are participating in searches for signs of new COVID-19 cases before infected people even have symptoms – by looking for the disease in poop.

Sampling of wastewater provides an “early warning” system at the population level, John Putnam, director of environmental programs at the Colorado Department of Public Health and Environment, said in a press release Wednesday morning. Most people start throwing the virus into their feces about two days after infection – before they develop symptoms and seek testing, he said. Although testing is not accurate enough to say that someone is infected in a particular household or neighborhood, it does give a signal or cases increase or decrease.

Utilities collect samples immediately before the wastewater enters their plants for treatment, said Jim McQuarrie, director of strategy and innovation for the Metro Wastewater Reclamation District. In Denver, they will sample two large pipes twice a week that serve a combined 1 million people, he said.

The sampling program costs the state about $ 520,000, with utilities donating their staff time to do the sampling. The participating systems serve more than 60% of Colorado residents.

Labs at Colorado State University and Metropolitan State University Denver will analyze the samples, and then send the data to the state health department. Health officials will then use the wastewater data, combined with nasal swab tests and other sources, to get a sense of which areas need more resources to deal with a growing caseload, said Nisha Alden, Respiratory Disease and COVID oversight program manager for CDPHE.

“We are considering this another tool in our oversight toolbox,” she said.

Researchers are still working out how much the virus level in the wastewater needs to change before it becomes a significant signal, said Nicole Rowan, manager of clean water for CDPHE. It will take at least a few months before they have enough data to draw conclusions, she said.