The dog days of COVID-19

A kid receives Covid-19 vaccination
Andrew Richter, 4-years-old receives the first dose of the Pfizer Covid-19 vaccination at the Mall of America vaccination on Wednesday, June 22 in Minneapolis. The CDC lists over 267,000 children under the age of 5 who have received at least one dose since it became available to this age group on June 18.
Kerem Yücel | MPR News

According to the Farmers’ Almanac, we’re in the dog days of summer (July 3 to August 11). Maybe the hot and lazy image that the term conjures is an apt characterization of where we are with COVID-19 in Minnesota: not overly concerning, not a lot of dramatic changes happening--but not entirely comfortable either.

Hospitalizations continue their downward trend, but cases, which had been on a very slow decline, have now plateaued completely. This suggests we may not be out of the woods yet on this wave. On the other hand, CDC’s community level risk rating indicates the best conditions in Minnesota since April, and much of the state is seeing a slow decline in COVID levels in wastewater too. More details below, plus a new look at how racial disparities in COVID hospitalizations have persisted—and changed.

And, as always, many thanks to David Montgomery, who continues to maintain the code that processes the Minnesota Department of Health’s data, even through their recent timing and format changes.

Plateau persists for cases and deaths, decline continues for hospitalizations

If we thought we were in a COVID plateau before, it’s even more the case now. This figure shows the rate of change from the prior week, for cases and hospitalizations. The most recent data point for cases is right at 0% change from the week before.

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Rate of change in COVID-19 cases and hospitalizations
The rate of change metric shows the recent plateau in more detail.
David Montgomery

This plateau is also pretty evident from our standard cases over time graph.

Minnesota COVID-19 cases by year
Cases have plateaued recently according to official reports.
David Montgomery

Hospitalizations are, despite some ups and downs, still on an overall downward trend.

Minnesota COVID-19 recent ICU and non-ICU hospitalizations
COVID hospitalizations are down from last month.
David Montgomery

Deaths remain in the same range of about five to six per day, although this data takes longer to become public.

Minnesota COVID-19 deaths by year
COVID-19 deaths have averaged around six per day for the last six weeks.
David Montgomery

For another look at how this wave has progressed, here’s a graph that shows the comparison of how many cases are reported compared to the number of cases at the start of a given wave. The main takeaway here is that this wave is persisting longer than past waves. (Take caution in comparing the magnitude of the spring 2022 peak with the previous waves given that availability and reporting of testing has changed throughout the pandemic.)

Percent increase in new cases by wave in MN
Although it hasn't resulted in as many hospitalizations and deaths, the spring 2022 wave has persisted longer than previous waves.
David Montgomery

CDC paints the state green!

This week’s “Community Level” map characterizes all but 3 of the state’s counties as low risk. The exceptions are Carlton, Pipestone and Rock counties, which are rated medium risk. This is the greenest map we have seen from the CDC since April 21, when all but two Minnesota counties were rated low on the community level risk ratings.

This does NOT mean that the CDC is sanguine about the level of COVID-19 transmission still happening in the state, however. Thirty-six Minnesota counties meet or exceed the CDC’s “high transmission” of at least 100 cases per 100,000 residents over a week. Another 39 are in substantial risk, with a weekly COVID-19 case rate of 50 to 99 per 100,000.

As noted in the maps below known COVID-19 case rates are currently highest in Carlton and Rock counties, and hospital admission rates (which also factor into the CDC’s aforementioned “Community Level” ratings) are highest in Rock and Pipestone counties.

Wastewater: Declining COVID-19 in Twin Cities despite BA.5’s ascendency

According to the Metropolitan Council and their partners at the University of Minnesota Genomic Center, the COVID-19 viral RNA measured in the state’s largest wastewater treatment plant was down by 11% when comparing the week ending July 4 to the previous week. This follows last week’s report of a minor 3% weekly increase.

The decline is especially welcome given that omicron subvariant BA.5 continues its ascendency, now comprising 62% of detected COVID-19 according to the Metropolitan Council. Just yesterday the New York Times characterized BA.5 as “the most transmissible variant yet,” warning that it could cause an upswing in cases as it has in several other countries.

COVID load in Twin Cities metro wastewater 7-7-2022
COVID-19 detected in Twin Cities Wastewater has declined in the most recent week.
David H. Montgomery | MPR News

The largely flat rate reported by the Metropolitan Council over the past couple of weeks is corroborated by the U’s parallel wastewater testing project. That project is reporting a virtually identical COVID-19 load in the Twin Cities Metro region over the week ending June 26 (at least when looking at the moving averages that they emphasize as most dependable).

A couple other regions of the state are faring even better, with both monthly and weekly declines reported in the Central and South East regions. Thankfully the trend appears to be turning the corner in the North West region, where wastewater measurements have shown steepest increases in recent weeks.

The second straight weekly increase in the South West region cancels out some of the promising decreases that had been reported for that region. The most concerning trend coming out of the regional-by-region wastewater testing is in South Central, which is seeing notable increases in viral load whether looking over the past month or week.

Minnesota hospitalizations by race and ethnicity

This week we also look at the department of health’s hospitalization data by race and ethnicity. Hospitalization rates over time have followed patterns that we’ve also seen in mortality data. Indigenous and Black Minnesotans have borne the highest rates.

Minnesota hospitalizations by race and ethnicity over time
Most recently, Black Minnesotans have the highest hospitalization rates.
Elisabeth Gawthrop | APM Research Lab
Minnesota ICU hospitalizations by race and ethnicity over time
ICU admissions remained high for a prolonged period for Indigenous Minnesotans during the delta and omicron waves.
Elisabeth Gawthrop | APM Research Lab

Another observation is that at the beginning of waves, it looks as though most groups are often on the same trajectory with similar rates, and then there’s a divergence with some groups leveling off or decreasing while other groups continue to see increasing rates.

One of the clearest examples of this is with the overall hospitalizations in spring 2021, with all groups tracking similarly and then only Black and Indigenous patients continuing with the increasing trajectory. That also happened at the beginning of the recent wave, with White and Black Minnesotans having a similar trajectory, and then rates of White patients leveling off and decreasing while rates of Black patients are still on the rise.

While those figures highlight some of the greatest differences in rates among race and ethnicity groups, it’s harder to see the trends within all groups. Here, the same data is grouped by wave of COVID in Minnesota. The waves are defined by where the lowest rates are in the valleys of the graph above.

Weekly hospitalizations by race and ethnicity during COVID waves
Black and Indigenous Minnesotans have seen the highest hospitalization rates.
Elisabeth Gawthrop | APM Research Lab
Weekly ICU hospitalizations by race and ethnicity during COVID waves
Indigenous Minnesotans have seen the highest rates of ICU admissions during the pandemic.
Elisabeth Gawthrop | APM Research Lab

Comparing over the different waves of the pandemic here in Minnesota, some things have stayed the same: hospitalization rates have often been highest among the state’s Black and especially Indigenous populations.

Some things have changed, however. As just one example, in our current wave average hospitalization rates are notably higher among White Minnesotans than they are among Latino Minnesotans. The opposite was true in the first three waves, especially during the initial onset of the pandemic.

To end on a hopeful note, despite the amount of COVID circulating in our communities, each race and ethnicity group has seen its lowest ICU rates of the pandemic during the current wave.