Minnesota shifts COVID tracking focus to severe cases

Minnesota's air quality has been adversely affected by wildfires

The Minnesota Department of Health has stopped reporting COVID-19 cases, a change aligned with similar measures at the federal level following the end of the national Public Health Emergency last month. The department noted in an email, “we are focusing our surveillance more on measures of severe disease and mortality rather than overall case counts/rates.”

As we have mentioned recently, case counts have also become less reliable measures of COVID trends given the move to more at-home testing, which doesn’t require reporting and people with milder COVID symptoms not necessarily seeking medical care. But MDH continues to collect and share data on COVID hospitalizations and mortality in the state.

While this means some of the data we have consistently reported on will no longer be part of this update, we still have wastewater data as an early indicator of shifts in COVID patterns. Wastewater has roughly tracked with cases when we’ve plotted the data together in the past.

Of more widespread concern in the realm of public health this week has been air quality, both in Minnesota and across the country, especially the eastern U.S. We dive into air quality data after the COVID update.

COVID-19 hospitalizations continue to fall, no spring rebound this year

Hospitalizations due to COVID-19, both ICU and non-ICU, continue to fall and are now consistently at levels not seen since the very start of the pandemic in March 2020.

Although there has been some fluctuation in COVID hospital admissions since the start of the year to now, especially with ICU admissions, there has been a clear downward trend in admissions over the last five months. There was a spring “rebound” of hospitalizations in 2021 and 2022 that did not materialize this year.

The downward trend in COVID-19 hospitalizations will certainly free up hospital beds for non-COVID patients, hopefully relieving some pressure on the state’s medical system. That being said, recent data from the Minnesota Department of Health showing the seven-day moving average for bed availability shows the Metro operating at low bed availability for pediatric and adult, non-ICU and ICU hospitalizations.

The northeastern portion of the state also has had low adult ICU bed availability, and the southeastern portion of the state has had low adult non-ICU bed availability.

New COVID hospitalizations in MN
COVID hospitalizations in recent weeks have fallen to lowest levels since March 2020.
David Montgomery

Deaths also continue to decline, albeit more slowly. From the latest confirmed data in mid-May, an average of three people per day died from COVID.  With declining hospitalizations, deaths will hopefully follow suit and drop further.

Minnesota covid-19 deaths by year
COVID-19 deaths continue to average around three per day in the state.
David Montgomery

COVID levels in wastewater continue to decline throughout the state

COVID levels in wastewater entering the Metro Plant fluctuated slightly since our last update according to the Metropolitan Council and the University of Minnesota’s Genomic Center.  

For the week ending June 4, there was a slight increase in levels but levels appear to decline again by week’s end. Even with a slight bump, recent levels in Metro Plant wastewater remain among the lowest seen over the last three years.

COVID levels in Metro wastewater by year
For the week ending June 4, COVID levels for wastewater entering the Metro Plant have fluctuated slightly but remain among the lowest seen over the last three years.
David Montgomery

The University of Minnesota’s parallel statewide wastewater analysis shows substantial declines throughout the state for finalized data through May 21.  

Four of the study’s seven regions saw a decline in COVID levels of 50 percent or more over the prior month, and two regions saw a decline of around 30 percent.

Over the prior week, the North West region experienced the largest decline, 70 percent, followed by a 62 percent decline in the South West region. The five other regions in the study had declines in their COVID levels between 42 and 47 percent.  

The one outlier this week is the study’s South East region, where COVID levels increased by nearly 300 percent over the prior month. Relatively speaking, this increase is half what it was in our update two weeks ago, when the region had an increase of nearly 600 percent over the prior month.

In that update, we reported that a spokesperson for the University of Minnesota Wastewater Surveillance Team noted to us that “they have previously seen large spikes with an equally quick return to low levels.” The latest data confirms that the levels are trending down and, if that trend continues, they will return to normal low levels.

Hazy days: How does Minnesota’s air compare?

Smoke from wildfires in Canada this week has blanketed much of the central and eastern U.S., including Minnesota. As reported by MPR News earlier this week, the state’s air quality so far this year has been the worst on record. How do our numbers compare to the pollution that’s turned the air over East Coast cities orange?

We took a look at the worst air quality days for roughly 100 locations around the country in the last 10 days. We analyzed both ozone and fine particulate matter, referred to as PM2.5. Ozone is typically worse on warm, sunny days with stagnant air.

Fine particulate matter can come from a number of sources, such as coal-fired power plants and diesel exhaust, but it’s the wildfires that have been the biggest driver of PM2.5 levels in recent days. Both are harmful to health, especially for sensitive groups like children and older adults, and those with respiratory or heart disease.

Compared to other U.S. states, Minnesota ranks in the middle of PM2.5 levels in the last 10 days, with the highest daily air quality index (AQI) levels around the state ranging from 71 in the Red River Valley to 153 in the Mississippi River Valley in southeastern Minnesota. Overall, conditions have been worse in eastern Minnesota, and June 5 and 6 were the worst days across most locations of the state.

The highest daily PM2.5 level among all the locations in our national dataset was in Lehigh Valley, PA, which includes the city of Allentown. That area saw a PM2.5 AQI level of 309 on June 7, putting it in the “hazardous” range on the AQI scale. New York City was also one of the worst locations, with a PM2.5 AQI of 254 on June 7. Casper, WY had the least pollution from fine particulate matter, with the highest PM2.5 AQI reading coming in at just 11.

One of the main causes of ozone pollution is the combination of car exhaust and sunlight, so ozone pollution tends to be worse in cities. In Minnesota, the worst ozone levels in the last 10 days were in the northern Twin Cities metro area and in Rochester, which both saw an ozone AQI of 122 on June 3. Northeastern Minnesota had the least ozone pollution, with the worst day’s reading staying in the “good” range at 26.

These numbers also rank Minnesota in the middle of ozone pollution levels across the country in the last 10 days. The worst ozone levels were in Philadelphia, with a reading of 200 on June 2. The best levels were in Honolulu, with a reading of 25 on June 7.

Smoke conditions have improved somewhat in Minnesota over the last few days, but a cold front moving through the state tomorrow will bring more smoke from fires in western Canada. This is according to the Minnesota Pollution Control Agency, which notes that the extent of the smoke impact is uncertain. Currently, the forecast is for moderate AQI levels tomorrow, with conditions improving after Sunday.