COVID-19 is not just another flu-like pandemic. Rapid rates of infection, spread, hospitalization and deaths relative to recent pandemics make it different. It is a new virus moving through a naive population. These factors produce a steep (exponential) growth curve compared to all other 21st C pandemics. We’ll also discuss data issues that make understanding past pandemic data and predicting the course of COVID-19 more difficult.

Isn’t COVID-19 another bad ‘flu season?

Comparison of coronavirus and other epidemics.
Coronavirus vs. Every 2000s Epidemic (March 19 update) Fatality comparison by Abacaba

Yes. And no. 

COVID-19 is a respiratory infection by the SARS-CoV-2 virus. This is similar to colds and flu in many symptoms (although different in some). Since we have been through few known SARS pandemics, a more data-rich comparison is with seasonal influenza pandemics. 

Flu pandemics are caused by a rapidly mutating family of RNA viruses (names like H1N1 designate sub-types of flu virus) that sweep around the world every fall and winter, infecting millions of people. These regular, predictable and well-studied pandemics vary greatly from year to year in ages affected, case rate and deaths. So, let’s look at COVID-19 vs flu pandemic history.

COVID-19 vs. flu pandemics in history

To put this in perspective (all data from US CDC

  • In an average flu season (October – May), 5-8% of Americans (20-26 million people) get sick, 200,000 are hospitalized and 30-40,000 die from flu or its complications. These are mostly the old (>65) and those with additional medical conditions, similar risk groups to COVID-19.
  • During this most recent flu (mostly H1N1) season (October 2019 – March 14, 2020), the US CDC estimates 38-54 million illnesses, 17-25 million medical visits, 390,000-710,000 hospitalizations and 23,000-59,000 deaths.
    2019-2020 US Flu Season: Preliminary Burden Estimates | CDC
    This is nearly twice as bad as an average flu season. Some of the excess cases and deaths in December and January may have been undetected COVID-19 infections.
  • In the 2009 (really 2008-2010) H1N1 (Swine Flu) pandemic, the US had some 61 million cases, 274,000 hospitalizations and an estimated extra 12,500 deaths (in addition to non-Swine flu fatalities). The peak was early, in October. In the US, this disease was more severe among young people than those over 65. An estimated 150-500,000 people died worldwide. The relatively low numbers of deaths in the US reflects the availability of intensive care to keep the most serious cases alive. https://www.cdc.gov/flu/pastseasons/0910season.htm

Note the wide range of many of these numbers. They are estimates. Many countries do not collect accurate flu data. Therefore, the number of people who contract the flu is undercounted. This is because many people get sick, stay home and get better but are never tested or diagnosed and thus not captured in the dataset. Death totals are low too. This is because many people who die while ill with flu have other conditions that may be coded as causes of death, such as bacterial pneumonia or unidentified respiratory viruses.

Historic and especially current pandemic data are dynamic and unclear. Interpreting statistics and making decisions based on them is difficult.

Data issues in flu history numbers and the COVID-19 pandemic.

We see similar data issues in the COVID-19 pandemic. First, countries differ in how they collect and code data. For example, Italy has been aggressively counting deaths, even conducting post-mortem tests and reclassifying pneumonia cases as COVID-19. On the other hand, Germany codes SARS-CoV-2 + patients with other diseases as dying of those other conditions. France does not count nursing home deaths. The PRC numbers are unreliable for political reasons. Moreover, when overstressed healthcare workers are focused on triage and saving lives, collecting accurate data takes a back seat. All these differences make the data hard to compare. 

In the United States we are still undertesting nearly everywhere, although we are beginning to catch up at the end of March. Hence, real case rates are undoubtedly much higher than confirmed rates (10-20X depending on which city, state or county). Moreover, the case fatality rate (CFR–deaths divided by case rate) is much higher than reality. This is especially true in places like King County, Washington, where the Kirkland nursing home outbreak produced more deaths (and more tests) than most other locations.

What is so different about COVID-19 vs flu pandemics?

However, what got so many people concerned in March, as you can see from the screenshots above and below and if you view the underlying video, is how rapidly confirmed cases, especially deaths, have been rising in the COVID-19 pandemic compared to flu history.

How COVID-19 triggered a worldwide mass response
Why COVID-19 triggered a mass response worldwide.

The video above tracked death rates for all serious (>500 deaths) epidemics

This video, mentioned above, tracked death rates for all serious (more than 500 deaths) epidemics since 2000. (The sci-fi synthwave chords-of-doom soundtrack is optional). If you go to his original video (https://www.youtube.com/watch?v=6dDD2tHWWnU) you will also see just how much worse the 1918 flu pandemic was! 

It would be interesting if the analysis included the ‘57 and ‘68 pandemics. While much less bad than ‘18, they were twice as bad as the swine flu pandemic death-wise (over a much smaller population) and therefore worse than many younger people have lived through.

Here’s an update on the daily death rate as of March 30, 2020. This exceeds the number of daily deaths estimated in the video above. Daily new confirmed deaths due to COVID-19

Historical pandemics and plagues.

For more historical information from the US CDC (from where the data above come), see Past Pandemics | Pandemic Influenza (Flu)

This Science News article with a nifty graphic, compares the previous four flu pandemics. As of the end of February, COVID-19 was still much smaller than any of those, but if the growth rate continues, could surpass them in April.

For the first time in history, we are trying to avoid, (in realtime!) falling into the classic case of devastating historical epidemics. Humans as a species have managed to survive multiple plagues throughout history. Although don’t forget, many millions of individual people did die. Past epidemics have made big differences in the course of history. Some historical perspective in this infographic: Infographic: The History of Pandemics, by Death Toll

Stay well!

Written by: Bonnie Feldman, DDS, MBA, Ellen M. MartinAnnie Rooker

For additional resources please read:

Let us know your thoughts!

The COVID-19 pandemic is a rapidly moving situation and it’s hard to keep up with the tsunami of information, misinformation, disinformation and the high noise-to-signal ratio, especially on social media. Let us know in the comments if you have good sources to share, have questions, or if you spot errors or outdated information in our posts. Also if there are additional topics you’d like us to tackle.

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