Excess Mortality in 2020

My last post of 2020 tried to end the year on an optimistic note: the rapid innovation of a new vaccine was truly a marvel. But I also warned you that I would have a post in the new year talking about the deaths of 2020 during the pandemic. And here it is.

Throughout 2020, I have tried to keep up with the most recent data, not only on officially coded COVID-19 deaths, but also on other measures. An important one is known as excess mortality, which is an attempt to measure the number of deaths in a year that are above the normal level. Defining “normal” is sometimes challenging, but looking at deaths for recent years, especially if nothing unusual was happening, is one way to define normal. The team at Our World in Data has a nice essay explaining the concept of excess mortality.

One thing to remember about death data is that it is often reported with a lag. The CDC does a good job of regularly posting death data as it is reported, but these numbers can be unfortunately deceptive. For example, while the CDC has some death data reported through 51 weeks of 2020, but they note that death data can be delayed for 1-8 weeks, and some states report slower than others (for reasons that are not totally clear to me, North Carolina seems to be way behind in reporting, with very little data reporting after August).

So there’s the caution. What can we do with this data? Since 2019 was a pretty “normal” year for deaths, we can compare the deaths in 2020 to the same weeks of data in 2019. In the chart at the right, I use the first 48 weeks of the year (through November), as this seems to be fairly complete data (but not 100% complete!). The red line in the chart shows excess deaths, the difference between 2019 and 2020 deaths. From this, we can see that there were over 357,000 excess deaths in 2020 in the first 11 months of the year, or about a 13.6% increase over the prior year.

Is 13.6% a large increase? In short, yes. It is very large. I’ll explain more below, but essentially this is the largest increase since the 1918 flu pandemic.

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