ESCANABA — The amount of detectable DNA from the virus responsible for COVID-19 in Escanaba’s sewer water has dropped, ending a holding pattern that has gripped the city since August.

According to the Sentinel Wastewater Epidemiology Evaluation Project (SWEEP), the last two samples submitted to the program from the Escanaba Wastewater Treatment Plant contained more viral DNA than 19% and 15% of all samples collected at the site since the city began participating in the program in August of 2021. The samples were dated Sept. 11 and Sept. 9, respectively.

Prior to the most recent samples, the city had consistently seen samples in the 48th to 53rd percentiles. That trend stretched back as far as Aug. 21, representing five separate samples, and followed an increase in detectable DNA that started at roughly the same time as the Upper Peninsula State Fair.

While the increase during and immediately following the fair may have been due to an influx of infected individuals converging on Escanaba and using the city’s restrooms, the fact the virus took hold suggests a certain amount of transmission between sick out-of-towners and otherwise-healthy Escanaba residents took place as well.

It is impossible to know exactly how many people have contracted the virus based on sewer data alone, as not all people who are infected with the virus develop symptoms and viral load varies even between individuals.

During the height of the pandemic in 2020, all testing for the disease was done in medically-controlled settings with results reported to the state. However, as home-testing became the norm, mobile testing sites vanished, and many tracking programs sunsetted, published infection data became less and less reliable.

Still, the Michigan Department of Health and Human Services (MDHHS) has continued to report the number of infections identified in healthcare settings, which serve as a barometer of infection trends. These numbers include tests performed by doctors or nurses for patients who are seeking COVID-19-related medical care and tests performed as part of routine care, such as before surgeries.

According to data from MDHHS, the entire state of Michigan is seeing an infection pattern that is very similar to 2023, but both less severe and with spikes and low-points of infection occurring about a month earlier. If the trend holds, Michigan can expect to see infections continue to fall until late-September, followed by a slight increase in infections, and in mid-October a substantial increase in infections that will peak sometime in November.

In the Upper Peninsula and at the county-by-county level, infections are less consistent with last year’s data. This is likely due to the lower population density of the U.P. compared to Michigan as a whole.

The following is the infection data for the Upper Peninsula for the week of Sept. 14 from MDHHS.

Gogebic – 6

Ontonagon – 5

Houghton – 20

Keweenaw – 3

Iron – 8

Baraga – 10

Dickinson – 19

Marquette – 42

Menominee – 9

Delta – 5

Alger – 0

Schoolcraft – 7

Luce – 0

Mackinac – 1

Chippewa – 18