Updated COVID-19 model: What it analyzes about the virus in Minnesota

Wednesday, state health leaders presented an updated model that is being used to help inform policy decisions in response to COVID-19 in Minnesota.

During a news conference, Stefan Gildemeister, state health economist with the Minnesota Department of Health, stated that the purpose of this modeling is to provide an understanding of the ever-changing nature of this virus.

Additionally, Gildemeister said the state has this model to serve as an educational tool for state leaders and the public to better understand potential outcomes of this virus.

Gildemeister iterated that the information resulting from the model is not specifically meant to be recommendations, rather, the information could help answer questions posed as a result of the virus.

The model uses specific scientific evidence, not hypotheticals, Gildemeister said.

Gildemeister also addressed the following:

Why are updates to this model necessary?

Gildemeister said COVID-19 is a new disease, with new evidence on the virus emerging daily. This model helps provide snapshots of the shape of the disease and the way it may play out in a population, he said. As new data becomes available, inputs must change.

Gildemeister also said the COVID-19 epidemic, as well as the evidence, is still new and data remains incomplete and limited.

What are the changes that were made to the model?

Gildemeister identified five key changes made to the model that was presented Wednesday.

1. Structural changes, to address asymptomatic infections and deaths occurring outside of hospitals.
2. Restricting the ICU metric to ventilated cases.
3. Updated parameter estimates, using newly-available data in the United States.
4. New calibrated parameters, including one calibration that accounts for the fact that a proportion of those over the age of 70 are dying from the virus in non-hospital settings as well as another calibration that takes into account a reduction in contacts under social distancing and the current ‘stay at home’ order.
5. A new model fit, meaning the model has been fitted to data on Minnesota deaths and hospitalizations through April 25. A model fit is a measure of how well the model displays a set of observations, or data points.

What is the updated model showing?

Gildemeister said the new model shows there is potentially less time to the virus peak in the state, as well as upward movement in ICU demand and full-epidemic mortality.

The updated model, Gildemeister said, demonstrates the effectiveness of some mitigation efforts has dropped from the original assumption input. For example, the model indicates the effectiveness of social distancing is now at about 38% rather than the originally assumed 50%; similarly, the effectiveness of the ‘stay at home’ order is now at 59.5%, rather than 80%.

Gildemeister said there are three scenarios being modeled.

One is a “no mitigation” scenario, a second is a ‘stay at home’ order through May 18 scenario, and a third is a ‘stay at home order’ through May 31 scenario.

In the first scenario, Gildemeister said the state would currently be in the midst of its virus peak. In the second scenario, the peak would occur toward the end of June. In the third scenario, the peak would occur at the beginning of July.

Meanwhile, ventilator demand would drop from about 5,000 in the first scenario to about 3,400 in the second scenario, to about 3,000 in the third scenario.

The mortality rate in the first scenario would be about 57,000, about 29,000 in the second, and about 28,000 in the third.

In terms of testing, Gildemeister said the data is complex and somewhat hypothetical at this point, as researchers consider both best- and worst-case scenarios. Under the “best-case scenario,” Gildemeister said researchers are seeing more time available until the peak, a lower mortality rate, and a smaller ICU/ventilator demand.

Moving forward, Gildemeister said state health researchers will be incorporating more, and better, data from the U.S. into the model as well as the refinement and enhancement of the model inputs, particularly as possible treatments become more readily available.

KSTP’s complete COVID-19 coverage

Meanwhile, Gov. Tim Walz is expected to extend Minnesota’s peacetime emergency declaration and is likely to modify the ‘stay at home’ order as well.

He is expected to make an announcement at 6 p.m. Wednesday.

Walz expected to extend peacetime emergency, likely to modify ‘stay at home’ order

Stay with 5 EYEWITNESS NEWS and KSTP.com for the latest updates.