Data shows increase in COVID traces

Ilsa Minor | Daily Press A guest of the Escanaba Kiwanis Club Home and Garden Show stops to talk to a gardening expert from Michigan State University Extension Friday. The show brings vendors and experts with knowledge about home improvements, gardening, and other ways to make a house a home.

ESCANABA — The amount of detectable DNA from the virus responsible for COVID-19 in Escanaba’s wastewater is increasing, according to the lates information from the Sentinel Wastewater Epidemiology Evaluation Project, commonly known as “SWEEP.”

According to SWEEP data, the last sample submitted to the project from the Escanaba Wastewater Treatment Plant, dated April 1, contained 37% more viral DNA than all other samples submitted by the plant. The sample is higher than the previous sample, dated March 27, with contained more viral DNA than only 18% of samples.

The increase marks a shift away from a declining trend in viral DNA. As of April 6, the 15-day moving trend suggests the amount of detectable virus in the city’s sewer water is rising by 100% to 999%, based on an exponential growth tracking system designed to mirror viral replication. This comes after a decreasing trend of -10% to -99% for all 15-day trends going back to March 23.

While the data suggests an increase in viral activity over the past 15 days, looking at a longer segment of SWEEP’s data suggests the city is in something of a holding pattern that started in early march, where the amount of detectable DNA swings back and forth by about 10-20 percentiles on a near-weekly basis.

The consistency can best be seen by comparing dates a few weeks apart in identical or nearly identical percentiles. For example, the March 4 and March 20 samples both were in the 14th percentile; March 11 and 26 were only a percentile apart, at 24th and 25th, respectively; and March 18 and the latest sample from April 1 were in the 36th and 37th percentiles, respectively.

This trend stands in sharp contrast to the spikes seen in November of 2023 or January of 2022, which where the two most-severe periods for viral activity seen by the city since it began participating in SWEEP in August of 2021. In those cases, the amount of viral DNA spiked quickly, with 1,000% or more increases often reported for 15-day moving averages.

While data collected through SWEEP serves as a good barometer of whether viral activity is ­increasing or decreasing in the area, it is impossible to know the exact number of COVID-19 infections in Escanaba or the severity of cases based on the SWEEP data alone.

At the start of the pandemic, prior to the rise of at-home testing, all tests were conducted in healthcare settings or at dedicated testing sites. That data was reported to the state for tracking, but there is no requirement — or mechanism — to report home test, which now represent the bulk of all tests.

Despite the hole in the data caused by the prevalence of home tests, the Michigan Department of Health and Human Services still tracks cases and deaths based on tests conducted by healthcare providers. The most recent MDHHS case data from the week of April 6 is shown below.

Gogebic – 32

Ontonagon – 2

Houghton – 5

Keweenaw – 1

Iron – 2

Baraga – 0

Dickinson – 1

Marquette – 9

Menominee – 9

Delta – 6

Alger – 1

Schoolcraft – 0

Luce – 1

Mackinac – 0

Chippewa – 4

It is important to note that the number of cases reported by MDHHS is the number of new cases. Cases that were identified in the prior week but are still active are not reported in the data.

While, with the exception of Gogebic County, the majority of the peninsula is experiencing a relatively low number of cases, there has been a substantial increase U.P.-wide in the number of deaths associated with COVID-19. According to MDHHS, Chippewa County, Dickinson County, and Houghton County each reported one new death during the week of April 6.


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