Genes that signal the presence of the virus that causes COVID-19 are increasing at many wastewater treatment sites around Michigan.
People infected with the virus shed it in their waste. The concentration of it found in wastewater is considered an early indicator of where COVID infections are heading.
The state monitors twenty so-called “sentinel sites” across Michigan. Michigan Department of Health and Human Services epidemiologist Susan Peters said most of them are seeing more COVID-related genetic material.
“Thirteen of our twenty sites are showing increased detections over the past fifteen days, compared to when we ran the data last week,” Peters said.
Signs of increasing COVID infections are starting to show up in reported case data too. The state reports a daily average of just over 1100 cases for the past week, compared to around 643 the prior week. The state now reports COVID numbers only once a week, on Wednesdays.
Most Michigan counties technically remain at a low level of transmission, according to the U.S. Centers for Disease Control. However, both the latest wastewater and case report data point to an upswing in infections, likely driven by the BA.2 or “stealth Omicron” variant of COVID-19.
Peters said wastewater data is considered a leading indicator of a possible COVID surge, but the timing can vary. “[For] some of our sites, it’s maybe a two to three day lead time,” she said. “Other times, it can be potentially as long as three or four weeks.”
There are other limiting factors. Most of the wastewater data is around a week old, and closer to two weeks in most of Metro Detroit.
“We’re still learning a lot from wastewater testing. It's a relatively new field, especially when it comes to applying it to COVID,” said Peters. “And so we're learning a lot, and there's still a lot more to learn about it as well.”
