COVID in slow decline across most of the state, but some 9 Minnesota counties still rated high-risk by CDC

A nurse adjusts a medical device.
ICU nurse Tanya Shaw makes an adjustment while working a shift Dec. 8, 2021
Paul Middlestaedt for MPR News 2021

Some good news on the broader COVID-19 front this week: the FDA approved vaccines for children age 6 months to 4 years of age, federal advisors recommended approval of a protein-based Novavax vaccine which may appeal to some who’ve resisted the mRNA-based vaccines currently in use, and a new analysis shows that April saw the lowest number of COVID deaths in the U.S. since the pandemic’s start.

Here in Minnesota, COVID-19 metrics across the board — wastewater data, cases, hospitalizations and deaths — are stable or slightly declining. But that doesn’t mean it’s declining everywhere. Nine counties, including St. Louis and Olmsted, are rated as high-risk by the CDC, meaning that masking indoors is recommended. We’ll go into these details, plus dive into some new COVID mortality data and explain why it’s important to factor in age when looking at racial disparities.

The big picture: Holding pattern persists

Statewide metrics show little change from last week. And despite some ups and downs in the data, cases, hospitalizations and deaths have overall stayed about the same in the last few weeks.

First, a look at cases. COVID-19 is on a slow decline according to the officially reported case data from the Minnesota Department of Health. Further, this trend is in agreement with the declining COVID levels we are seeing in wastewater data (more on that below.)

One important caveat to keep in mind when comparing current case rates with past years of data: there are likely many more cases now that are unreported compared to this time last year, due to the proliferation of at-home tests that go unreported.

Minnesota COVID-19 cases by year
Minnesota COVID-19 cases by year
MPR News | David Montgomery

Hospitalizations provide a better relative comparison over time. Both ICU and non-ICU admissions have stabilized and are at similar levels as they’ve been at this time the last two years. Although hospitalizations are higher than earlier this spring, they are still below where they were for the entire period of late summer 2021 through early February 2022.

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New ICU and non-ICU COVID hospitalizations in MN
New ICU and non-ICU COVID hospitalizations in MN
MPR News | David Montgomery

Deaths have gone down a bit since a spike last week, but we don’t know if that’s the beginning of a true downturn. Compared to much of the pandemic period, deaths are still relatively low. And deaths have also stayed about the same, averaging about four per day.

Minnesota COVID-19 deaths by year
Minnesota COVID-19 deaths by year
MPR News | David Montgomery

Regional data: COVID down again in wastewater

Last week we highlighted the Metropolitan Council/University of Minnesota’s Genomic Center’s findings that COVID-19 levels were down by 16 percent. This week COVID levels are down by an additional 12 percent.

COVID load in Twin Cities metro wastewater
COVID load in Twin Cities metro wastewater
MPR News | David Montgomery

In addition, the Metropolitan Council is reporting that BA.4 and BA.5, highly contagious omicron subvariants, continue their ascendency and now make up 32 percent of COVID-19 material in their measurements.

According to a parallel wastewater tracking project at the University of Minnesota’s Medical School COVID levels are now down in six of the state’s seven regions. Levels are still up in the combined samples from the three treatment plants located in the northwestern counties of Beltrami, Clay and Pennington. This follows last week’s reported weekly decreases in the Twin Cities, Central and South East Minnesota.

Perhaps even more meaningful: longer-term monthly trends are down in the wastewater samples from the plants in South Central and South East Minnesota, and flat in both the Twin Cities and Central regions.

County-level data: CDC warnings up a little and down a lot

The bad news from CDC’s weekly Community Level ratings released yesterday afternoon is that nine counties are now in the high-risk category, up from five counties last week. The CDC recommends that people in these orange counties — now including Duluth’s home of St. Louis County and, once again, Rochester’s home of Olmsted County — wear masks indoors.

The good news is that the number of counties at medium risk dropped from 47 to 32. Most of the Twin Cities metro, including Dakota, Hennepin, Ramsey and Washington counties, remain in the yellow, but several counties in the central and northern parts of the state have now turned green.

The CDC’s risk ratings are based on high case levels and/or high hospitalization rates. You can see those numbers if you hover over the map above. In addition, we have now posted maps showing that underlying data on our website.

From those maps you can see, for example, that in Traverse and Big Stone counties, the bump on Minnesota’s western edge, are rated as orange on the CDC’s map due to their state-leading new hospital admission rates. And one county over to their east, Pope County, is orange because it has the state’s highest weekly case rate again this week.

Why age is important when talking about COVID disparities

There was a bit of a brouhaha last week when the New York Times published some analysis of COVID mortality and race. In short, the Times’ David Leonhardt wrote that COVID’s racial gaps have narrowed and even flipped, while public health experts such as Gregg Gonsalves and Katelyn Jetelina, argued that leaving age adjustment out of the analysis was misleading.

Before the Times article came out, we at APM Research Lab also published an article on this topic, noting both the age-adjustment factor as well as the fact that “the gaps did close somewhat, largely because death rates among whites grew toward the higher rates of BIPOC groups.” Not exactly good news.

Age adjustment is a statistical technique to help account for the fact that 1) COVID carries higher risk for older populations and 2) race and ethnicity groups have different age distributions. White Americans, for example, live longer than Black Americans on average.

So, within the relatively older white population, there is a greater share of people who have lived long enough to be at greater risk of getting severely ill or dying from COVID. That is going to lead towards a greater mortality rate within the white population simply because of the risk to seniors.

This is not to say we should ignore the risk that age carries, for all race and ethnicity groups. But, if we want to specifically understand when a racial or ethnic identity carries more risk, we have to factor out the age component. That’s what age-adjustment does.

For these reasons, we conduct an age adjustment on COVID mortality rates for the APM Research Lab’s Color of Coronavirus project. We’ve just updated that page this week to include deaths through the end of April. Here are our current calculations by race and ethnicity for both crude and age-adjusted rates in Minnesota.

Minnesota COVID mortality rates by race, crude and age adjusted
Elisabeth Gawthrop | APM Research Lab

It’s admittedly not a perfect analysis — it’s a statistical estimate that relies on assumptions, and in places where a racial or ethnicity group is low enough in population, it can be unreliable. But public health experts have told us that in most cases the age-adjusted rate is going to better reflect the differential risk to racial and ethnicity groups than the crude mortality rate does.

Another drawback of the age-adjusted rate is that it’s also a bit hard to wrap one’s head around, conceptually, and thus hard to communicate to the public. Another technique that is a bit more straightforward to understand is to directly compare mortality rates within a smaller age range.

A group at U of M is doing just that. Their work, led by Elizabeth Wrigley-Field, focuses on mortality in Minnesota just in the 45- to 64-year-old range, and they also fold vaccination rates for the same groups into their analysis.

They find that Native Minnesotans in the 45-64 age range have the lowest vaccination rates and — by far — the highest mortality rates during the delta and omicron waves.

Period-specific vaccination rates and Covid-19 mortality rates
Period-specific vaccination rates and Covid-19 mortality rates at midlife (ages 45- 64) by race/ethnicity in Minnesota. Panel B depicts the race-specific mortality rates at midlife during the pre-vaccination period, mid-vaccination period, Delta period, and Omicron period of the pandemic. Panel D ranks racial groups by percent unvaccinated and mortality rate during Omicron period (January 2022 to April 2022). All mortality rates are annualized to facilitate comparison across periods. Provided by the authors.
Wrigley-Field et al.

And, as shown in the figure, they also find that white middle-aged Minnesotans have the second-lowest vaccination rates and the lowest mortality rates. As they say in their conclusion, “if the current period is a ‘pandemic of the unvaccinated,’ it also remains a ‘pandemic of the disadvantaged’ in ways that can decouple from vaccination rates.”

Note: this figure was given to us by the authors in advance of the public release of their most recent update. Their previous update is available here, and their data repository is available here. Both will be updated soon, at the same links, they said. Also worth noting is that this work is being submitted for peer review but has not yet gone through that process.

The upshot of all of this: whether applying age-adjustments or comparing similarly aged groups of different racial groups, it is apparent that significant gaps persist between the lower mortality rates of white Americans and the higher rates of Black, Latino, Pacific Islander, and especially Indigenous Americans. This remains the case even though white Americans have lower vaccination rates, which has led to higher death rates among that group than otherwise could be the case.

Have a happy and safe Father’s Day / Juneteenth weekend!