A Tale of Two Months - August 2021 and October 2020

The Illinois Department of Public Health (IDPH) reported 149 new COVID cases for the month of August. That’s the fourth higest monthly total we’ve ever experienced and more than May, June and July combined. It’s hard not to see this trend as the start of a new surge in cases. To top things off, on September 1 the IDPH reported 17 new COVID cases. Excluding a few recent days that hit double digit case nubmers, that’s the most we’ve seen in a day since December.

For this post I’m going to look at two months: October 2020 and August 2021. For Warren county these months have the third and fourth highest case counts to date. October marked the start of last fall’s surge in cases, and unless things turn around soon August seems to be poised on ushering in a new fall surge. All the data presented in this post comes from the IDPH. For some context and because of the close knit nature of the two counties, I’ll be looking both at Warren and Knox county.


The pandmic has streched over 19 months thus far and it’s important to put our two target months in context. Let’s start by looking at the weekly case numbers for both Warren and Knox County for all 19 months of the pandemic. Below you’ll see actual numbers in the first row and cases per 100,000 people in the second. October 2020 and August 2021 have been hightlighted in red.

We can see the effects of the population difference in the first row. Knox has a larger population and has more cases as a result. When we look at the second row, which factors in the size of the population and normalizes to a per 100000 person basis, you can see that the two counties have had relatively similar experiences. Warren started off with more cases back in April and May of 2020 and Knox might have seen more cases this past April, but all in all the trajectory of the pandemic in the to neighboring counties has been similar. This makes perfect sense as they neighbor one another, there is regular traffic between the two counties, and with that traffic will come the virus.

The similarity also means that our target months play the same role in the counties pandemic history. October marked a clear start in the fall and winter surge and this August seems to be a clear departure from relatively low spread during the summer months. October 2020 ranks third for the most cases reported in a month for both counties. August sits at fourth in Warren and fifth in Knox.

What the historical data indicates is that for both Warren and Knox county, October 2020 and August 2021 both mark a noticable departure from the months that proceeded them. October came on the heels of months of moderate spread and heralded the start of our a major surge in cases. This past August marked a clear and sudden departure from months of low viral spread in the area. The sudden shift from low to substantial spread might seem suprising, but if you’ve followed the national Covid new, then you’ll know that it’s almost certainly driven by the Delta variant.

In October, we were dealing primarily with the original strain of Covid. Nobody was vaccinated. The virus was clearly present and as the temperature cooled and people retreated inside, the virus took hold and surge began. Over the summer we had modest levels of vaccination in the community and that certainly helped keep case counts low. By August Delta had made it’s presence known in the area and now threatens a new surge.

Who is Getting Sick?

The suddenness of the rising in cases this past August is just one indicator that we’re dealing with the Delta variant and a new phase of the pandemic. Another big difference can be seen by looking at the ages of those getting sick. In Warren county the difference between October and August is quite dramatic. Knox is less dramatic but still exhibits some of the same patterns. Below you can look at actual case numbers by the IDPH reported age groups for each month as well as the percentage of the total cases for the month that each age group represents. The tables are sorted from most to least number of cases.

Here in Warren county we see a near flip in the age demographics between October and August. In October the top four age groups were over 40 years old with just under 50% of the total cases being between the ages of 40 and 69. This past August just about that same porportion is coverd by those under the age for 40 with the under 20 group reporting the most cases for the month by a fairly large margin; The under 20 group accounted for just about 29% of the total cases reported in August. This change makes sense given that many, if not most, of this group is unvaccinated and that the Delta variant seems more able to infect children than the variant we were dealing with in October. What really jumps out to me is that in October cases seemed pretty evenly distributed across six of the nine demographic groups. In August the cases are more concentrated in just two or three groups.

Knox county has seen a similar demographic shift. The under 20 group also held the top spot this past August and accounted for nearly 22% of the total cases reported. While the age shift is less pronounced in Knox, some flipping is still present. The 40-49 age bracket accounted for 10% of the cases in October but jumped to 16% in August. The concentration of cases into just a few groups is less pronounced in Knox county, but is still there and still driven by a jump in cases in the under 20 crowd.

What’s Next

The Governor of Illinois has mandated indoor mask wearing and vaccination for all school workers. The Pfizer vaccine has been granted full FDA approval and as a result a good number of businesses are starting to mandate vaccines for their employees. Hopefully these measure turn the tide of this surge and we see a drop in cases for September. As a parent of two children under 12, I’m anxious to get them vaccianted as these data make it clear their age is no longer affording them the kind of protection it did back in October. They’re back in school doing face-to-face learning and I really, really want them to stay there. It seems like nobody is interested in future lock downs and returns to remote learning. I know I am not. What seems clear from the August data is that in order to avoid the extreme measures that followed last October, we’ll need to step up other protective measures and find ways to combat the delta variant and the new challenges that it brings.