It's time to visit Florida again - graphically

In May, I showed the following chart that presents a way to understand excess deaths in Florida (link to post):

It was only two months into the pandemic: because actual deaths from death certificates take time to count, it was just a sign of things to come. We start with a projection of expected deaths as by seasonal flu ("pneumonia & influenza") made based on prior flu seasons, expressed as a percentage of total deaths by any cause. In the first two months of the pandemic, the reported deaths by seasonal flu was as much as double the typical percentage of all deaths. On top of that, there were deaths related to Covid-19, which were roughly equal to deaths by seasonal flu during April.

There was no particular reason why seasonal flu deaths should be significantly above normal during the tail end of the 2019-20 flu season so it was suspected that Florida might have been undercounting Covid-19 deaths.

Months later, most of the dust has settled on these earlier months, and many of those deaths appeared to have been reclassified as Covid-19 related. I revisited this analysis below.

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Let's start with seasonal flu statistics for the past five seasons (from 2015-6 to 2019-2020).

Flu-counting starts in late September/early October each season. According to the CDC, flu season typically reaches a peak in the winter, and lingers on till as late as May. Pneumonia & influenza accounts for 1 to 2 percent of total deaths in any given week of the year, on average in the four seasons prior to 2019-2020. The 2019-20 flu season was a bit late arriving so when Covid-19 cases started getting detected in March, flu deaths were just easing from the seasonal peak.

The above chart - specifically, the thick gray line - establishes what we expect the flu fatalities to be during the pandemic months from March to Oct 2020. The orange lines show the actual deaths attributed to seasonal flu. These counts are definitely smaller than the numbers I found back in May. The revised counts make more sense since the flu is seasonal. (I left out the November data because they are incomplete at the time of writing.)

What happens when we layer on the Covid-19 deaths?

The spike of data ran off the page.

I kept the scale of the lower part the same as before. In March and April, while pneumonia and influenza accounted for 1 to 2 percent of all deaths in Florida, when Covid-19 were lumped with the other two causes, they reached about 8 percent of all deaths, roughly four times as many. In the summer months, over a quarter of the deaths in Florida were linked to Covid-19, pneumonia or influenza.

In a normal flu season, we might see 50 to 100 deaths per week in Florida due to pnuemonia or influenza. Since April, Florida has suffered Covid-19 deaths in the hundreds, and during the peak in the summer, over a thousand per week, roughly 10 times above expectation.

Here's a gif that shows the top of the chart:

 

 

 

Comments

[Ken]

Flu deaths are probably down due to physical distancing and restrictions on visiting aged care homes.