Since the middle of March, I've been tracking the daily COVID-19 statistics for Illinois in a spreadsheet. When I started doing this, I would watch Dr. Ngozi Ezike (the head of the Illinois Department of Public Health) announce the numbers for the previous day at the governor's daily press conference. Over time, those daily press conferences ended, but the numbers are still posted online each afternoon. So each day I get those numbers and plug them into the Google spreadsheet I created, and a bunch of formulas churn out all the data points I'm interested in.
My main reason for doing this is so I can create the charts I want to see. Now that I've got about 3 and a half months worth of data, I thought I'd share those charts.
I started out by charting the number of positive cases each day:
It's an interesting chart, but one day Dr. Ezike said that when you see a day or two of decreases, you can't assume it's a trend. To detect trends, you really need to look at weekly data. So I made a chart summarizing the data by each week. I have to confess it took me a really long time to figure out how to make the chart and get the axes labeled correctly. So here are the positive cases in Illinois summarized by week:
As you can see, we reached a peak the first week of May, and its been steadily declining until this week, which saw a small increase (up 17% from last week).
Here's the weekly data for COVID-19 deaths in Illinois:
It also peaked the first week in May.
Lately I've been reading articles about other states having a record high number of positive tests. What I really want to know when I read those stories is what is the percentage of positive tests in those states and is it changing? I recently created this chart to see what that looks like for Illinois:
Outside of one 47% outlier, Illinois peaked in the low to mid 20% positive range. For the past couple of weeks, Illinois has been steady at 2-3% of tests being positive.
At one point, Illinois saw a jump in the number of positive tests, which caused some concern among the public. The governor and Dr. Ezike assured everyone that it was okay, because the percent of positive tests was staying the same. The high number of positives was just because we ramped up the number of tests being performed. Last I heard, there were 3 labs in the state, one in north, one in the central, and one in the south, which were running tests 24/7. Here's a chart I made just now, looking at the number of tests performed in Illinois:
For the most part, Illinois has done 20-30,000 tests per day, but the past 3 days have all been over 30,000.
Finally, I've been keeping track of the numbers for McHenry County. Here are the weekly totals for positives and deaths.
Both peaked the first week in May, and this week saw a sizable 35% increase in positive cases.
It will be interesting to see how all of these numbers change in the future.