COVID-19: How unusual is the age distribution of deaths?

The University of Oxford’s Centre for Evidence-Based Medicine recently compared the age distribution of COVID-19 deaths with deaths from the 2009 flu pandemic (which is estimated to have killed 150,000-575,000 worldwide).1 One remarkable aspect of the 2009 flu was that it resulted in disproportionately greater mortality among younger and generally healthier people than in a typical flu season. This fact drove news media coverage early on in the pandemic.2 Indeed, some articles offered dire warnings that deaths due to the 2009 flu were “likely to be higher [than seasonal flu] simply because the virus will infect far more people than normal, and it kills directly more often.”3

The 2009 flu disease itself eventually proved to be “no worse than seasonal flu,”4 and caused far fewer deaths in the United States than other flu seasons; an estimated ~12,000 deaths (8,700–18,000)5 compared to 61,000 (46,000-95,000)6 for the 2017-18 flu season. Nevertheless, the shift in mortality towards younger individuals is a hallmark of pandemics.7

The CDC estimated in 2010 that 87% of deaths attributed to the 2009 flu pandemic were among those under the age of 65.8

https://www.cdc.gov/h1n1flu/estimates/April_March_13.htm

By comparison, the CDC’s provisional death count of COVID-19 reported to the National Center for Health Statistics (NHCS) shows that as of April 11, 22% of such deaths are among those under the age of 65.9 It’s important to note that the total reported here is approximately half the CDC total at that time due to the lag in submission of death certificate data to NHCS.

https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm

The relatively low mortality among younger individuals is even more pronounced in data from Italy (through March 30th) where 16.4% of deaths attributed to COVID-19 were among those under age 70.10

https://www.epicentro.iss.it/coronavirus/bollettino/Bollettino-sorveglianza-integrata-COVID-19_30-marzo-2020.pdf

The corresponding data for influenza and pneumonia deaths in 2017 in the US are provided below.11 Deaths among those under age 65 make up 15.8% of the total. While some of the pneumonia deaths included for 2017 might not be related to influenza, recall that the CDC estimates 61,000 deaths attributable to influenza during the 2017-18 flu season, as mentioned above.

https://www.cdc.gov/nchs/data/nvsr/nvsr68/nvsr68_09-508.pdf

As CEBM points out, the age distribution of COVID-19 deaths is more similar to that seen in seasonal influenza than in previous pandemics.


[1] Roos R. “CDC estimate of global H1N1 pandemic deaths: 284,000”. CIDRAP. June 27, 2012. Retrieved April 16, 2020.

[2] DeNoon D. “H1N1 Swine Flu Deadly to the Young”. WebMD. October 20, 2009. Retrieved April 16, 2020.

[3] Mackenzie D. “Swine flu myth: This is just mild flu. The death rates are even lower than for normal flu”. NewScientist. October 28, 2009. Retrieved April 16, 2020.

[4] DeNoon D. “H1N1 Swine Flu No Worse Than Seasonal Flu”. WebMD. September 7, 2010. Retrieved April 16, 2020.

[5] “2009 H1N1 Pandemic”. Centers for Disease Control and Prevention. June 11, 2019. Retrieved April 16, 2020.

[6] “Estimated Influenza Illnesses, Medical Visits, Hospitalizations, and Deaths in the United States- 2017-2018 influenza season”. Centers for Disease Control and Prevention. November 22, 2019. Retrieved April 16, 2020.

[7] Vanderbilt University Medical Center. “Over-reactive immune system kills young adults during pandemic flu.” ScienceDaily. December 6, 2010. Retrieved April 16, 2020.

[8] “CDC Estimates of 2009 H1N1 Influenza Cases, Hospitalizations and Deaths in the United States, April 2009 – March 13, 2010”. Centers for Disease Control and Prevention. April 19, 2010. Retrieved April 16, 2020.

[9] National Vital Statistics System. “Coronavirus 2019 (COVID-19) Surveillance”. Centers for Disease Control and Prevention. April 15, 2020. Retrieved April 16, 2020.

[10] “Epidemia COVID-19”. epicentro.iss.it (in Italian). Istituto Superiore di Sanità. March 30, 2020. Retrieved April 16, 2020.

[11] Kochanek KD, Murphy SL, Xu JQ, Arias E. Deaths: Final data for 2017. National Vital Statistics Reports; vol 68 no 9. National Center for Health Statistics. 2019. Retrieved April 16, 2020.

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