Use Hospitalization Rate, not Positivity, to Assess Mitigation

Earlier this week, Illinois Governor JB Pritzker imposed new COVID-19 restrictions on
businesses in the Illinois Department of Public Health COVID-19 Region 4 (Randolph,
Monroe, St. Clair, Madison, Washington, Bond, and Clinton Counties). He based these
actions on the aggregate COVID-19 positivity rate for Region 4 that had risen above an
8% threshold. Governor Pritzker states that these restrictions will not be lifted until
Region 4’s positivity rate drops below 6.5%. While I agree that it is important to monitor
the positivity rate for our region, I believe that the COVID-19 hospitalization rate is a
much better barometer for determining what mitigation efforts are needed.

When Governor Pritzker first announced a statewide response to the COVID-19
pandemic back in March, he explained the purpose of our actions as an attempt to
“flatten the curve” so that hospital capacity would not be overwhelmed. The hospital
admission rate metric directly relates to our regional hospital capacity. This metric and
the amount of COVID-19 patients occupying intensive care unit beds allow us to
evaluate whether our hospitals remain in position to treat patients. From July 5 th through
August 29 th , the COVID-19 hospitalization rate for Region 4 has remained relatively
steady and does not indicate that our region’s hospitals are in danger of being overrun
by COVID-19 patients.

On the other hand, the positivity rate, while a useful metric to assess whether public
health officials need to increase the amount of COVID-19 testing, is not an accurate
forecaster of whether our hospital capacity is about to be overwhelmed. IDPH’s own
data backs up this assertion. From July 5th through August 28th, as the Region 4
positivity rate climbed from 4.8 % to 10.4%, the hospitalization rate only increased by 2
patients from an average of 4 admissions per day to 6. On August 29 th , it dropped back
down to 5 admissions per day.

I also question whether the positivity rate accurately depicts the amount of COVID-19
present in our southwestern Illinois communities. The COVID-19 positivity rate does not
represent the amount of positive individuals in our communities. Instead, the positivity
rate simply gives the percentage of administered COVID-19 tests that come back
positive. Furthermore, the positivity rate is also based on test results—not individual
patients. This means that one COVID-19 positive individual who is tested at multiple
times during their treatment will contribute a significant number of positive test results to
the positivity rate calculation. And even that data may still be incorrect. On August
29th, the New York Times published an article arguing that the methodology for COVID-
19 testing likely generates positive results from statistically insignificant genetic virus

In addition to problems with data accuracy, I also believe that IDPH is making a mistake
by including data from state facilities in its positivity calculation. The individuals
generating these positive test results are confined to their facilities and not members of
the general public. Not only are these individuals not a part of community spread, but
the general public has no ability whatsoever to influence behavior at these facilities.
Their test results should not be included in the positivity data pool.

Adjusting a flawed plan is a sign of strength and leadership, not weakness. Governor
Pritzker should recognize that his mitigation plan announced on July 15 th was mistaken
by making mitigation measures contingent upon the least reliable metric, the positivity
rate. Instead of using the positivity rate, Governor Pritzker owes it to the struggling
small business owners of Illinois to update his mitigation plan and use the COVID-19
hospitalization rate as the benchmark for any new restrictions to combat the novel
coronavirus in our communities.
State Senator Paul Schimpf
58 th Legislative District