Wastewater showing recent COVID declines in Twin Cities, no new strains 

A man fills a test tube with a sample of water.
Steve Balogh, principal research scientist at the Metro Plant in St. Paul, prepares samples of wastewater in a lab on March 3. Metropolitan Council environmental services staff extract RNA or genetic material from SARS CoV-2 from the samples, then send it to the University of Minnesota Genomics Center, where scientists measure the amount of viral RNA. Balogh said so far, concentrations of the virus in wastewater have closely mirrored the changing infection rates in the Twin Cities.
Courtesy of Metropolitan Council

As our round up of the week’s data will show, we have a second consecutive week of mostly hopeful new info about COVID-19 as shown in everything from wastewater data to cases to hospitalizations. 

It could be the beginning of the end of the plateau-like wave that rose in the spring and hasn’t gone down since. We take a look hospital metrics around the state over the course of this wave.

We are far from out of the woods on this, however. The Minnesota Department of Health is reporting nearly 2,300 COVID-19 deaths this year, including 31 so far confirmed in August. This is higher than the number of deaths reported for the same period last year at 2,040.  

In addition, this week the New York Times reported that, driven by a heavy COVID-19 death toll, the average life span of Indigenous Americans has decreased by nearly seven years. And from our own Color of Coronavirus project, we know that Indigenous Minnesotans die of COVID at an even higher rate, once adjusted for age differences, than is the case nationally. 

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With that in mind, let’s get back to this week’s mostly hopeful data.

Is momentum building on our downward slope? 

With the usual caveat that this pandemic has been nothing if not unpredictable, the current trends of cases and non-ICU hospitalizations are headed in a good direction. Cases continue to fall across all regions in the state, and non-ICU admissions are down from a peak of 73 per day in mid-August to more like 50 per day a week ago (this week's data is still coming in). ICU admissions have hovered around eight per day since mid-July.

Weekly COVID-19 cases in Minnesota regions
Cases have been going down in all regions of the state for several weeks.
David Montgomery
New ICU and non-ICU COVID hospitalizations in MN
Non-ICU hospitalizations have steadily declined in recent weeks.
David Montgomery

Compared to previous points in the pandemic, ICU hospitalizations have stayed well below the peaks of previous waves. Non-ICU hospitalizations have also stayed below the high points of previous surges, but were much higher this summer than the previous two summers. A major question is whether the seasonal trend of increasing hospitalizations in the fall will repeat itself in the coming months.  

Comparison of ICU and non-ICU COVID hospitalizations throughout pandemic
A major question is whether the seasonal trend of increasing hospitalizations in the fall will repeat itself in the coming months.
David Montgomery

Among the otherwise hopeful signs this week is a sobering trend of increasing deaths in the last couple of weeks. This data hasn't been finalized, and it's a bit hard to see the dotted line of incomplete data, but it looks as though July's peak, which was a seven-day rolling average of seven deaths per day, was met if not eclipsed in late August. We can hope that the recent decline in hospitalizations will translate to decreasing deaths soon. 

Minnesota COVID-19 deaths by year
Deaths have increased in recent weeks.
David Montgomery

Wastewater showing recent declines in Twin Cities and no new strains 

The most recent wastewater analysis in the state, from the Metropolitan Council and the University of Minnesota’s Genomic Center, shows a second consecutive week of declining COVID levels. There was an 11 percent decline for the week ending Sept. 5, following the 19 percent decline reported last week.  

Although the period of the most recent wastewater analysis coincides with the Great Minnesota Get-Together — the State fairgrounds are serviced by the Metro Plant — a spokesperson for the Metropolitan Council said that there is “no indication of any effect on our numbers” from the State Fair.  

COVID load in Twin Cities metro wastewater 9-9-22
The Metropolitan Council is reporting a decline in COVID-19 as measured in wastewater.
David H. Montgomery | MPR News

Perhaps equally good news from the Metropolitan Council’s summary: “BA.5 constituted 90 percent of the viral RNA entering Metro, and BA.4 and BA.2 represented six percent and one percent, respectively, of the total viral RNA load. We are testing for BA.2.75 but have not seen it in Metro influent.” In other words, for the time being they are not detecting new strains that could send trends back up. 

The latest data out of the University of Minnesota’s Wastewater SARS-CoV2 Surveillance Study, tracking data from seven regions through Aug. 24, shows a mixed picture. The single largest region, the Twin Cities, is basically flat, while both monthly and weekly increases were observed in Central and South East treatment plants. COVID levels declined in the South West region over both the past week and month, while the North East and North West saw a decline only in the most recent week.  

Minnesota is even greener than last week, according to the CDC 

In the Centers for Disease Control and Prevention’s latest weekly “Community Level” COVID-19 assessment, even more counties are rated low-risk than was the case last week: 67, up from 55. This is the most green space we have seen on this map since early July. 

The CDC’s analysis puts only two Minnesota counties in the high-risk category this week: Lincoln and Martin, both in the state’s southwest. The CDC’s guidance for residents of these counties includes masking up when in indoor public places. 

The CDC’s “Community Level” map takes into account both COVID-19 case rates and hospitalizations. However, if we look only at the latest weekly case rates, 55 of Minnesota’s 87 counties meet the CDC’s threshold for high transmission (100+ weekly cases per 100,000 residents). Lincoln County has the state’s highest rate, with 390 officially reported cases per 100,000 for the week ending Aug. 31. Weekly case rates exceed 200 per 100,000 in five counties: Koochiching, Mahnomen, McLeod, Redwood and Traverse. 

Hospital data from the plateau summer 

As we cross our fingers that the current downward trend will continue, what does the data show about which places have seen the most hospitalizations and pressure on hospitals during this summer's plateaued wave?  

The CDC releases hospital admission and bed utilization rates for COVID at the "health service area" level. Below we've mapped these rates since April 1, 2022 – the approximate beginning of this plateau-like wave. (Note: while the data is mapped by county, it's calculated per health service area, which you can see on hover in the below maps.) 

The highest average bed usage (5.5 percent to 5.7 percent) stretches from Mille Lacs and Kanabec counties to the north, around the east side of the Twin Cities Metro, to Rice County to the south. The rest of the Metro as well as the health service area with Faribault and Freeborn counties are not far behind at 4.9 percent and five percent, respectively. The western flank of the state has had overall lower bed usage in comparison. Admission rates, however, have a somewhat different regional pattern, with the highest rates in the southern part of the state.  

We also looked at some of the highs and lows for these metrics across the state. 

For COVID hospital admission rates: 

  • Lowest current rate: 1.5 people per 100,000 in the health service area that includes Blue Earth, Nicollet, Waseca and Watonwan counties 

  • Highest current rate: 27.7 people per 100,000 in the health service area that includes Martin County (as well as counties in Iowa) 

  • Highest weekly rate since April 1, 2022: 42.3 people per 100,000 in the health service area that includes Roseau and Lake of the Woods counties (week of May 12, 2022)   

For COVID inpatient bed utilization: 

  • Lowest current percent: One percent of inpatient beds in the health service area that includes Pennington, Marshall, Kittson and Red Lake counties  

  • Highest current percent: 7.5 percent of inpatient beds in the health service area that includes only Rice County 

  • Highest weekly percent since April 1, 2022: 14.6 percent of inpatient beds in the health service area that includes only Rice County (week of Sept. 1, 2022) 

And finally, there's been only one health service area (Beltrami and Clearwater counties) with hospital admissions increasing consistently over the past couple of weeks.