Friday, June 12, 2020

Influenza/Pneumonia Experience Offers Lessons for Covid-19

In only a few months, U.S. covid-19-related deaths surged past 100,000.

To put that in perspective one can examine the nation’s annual mortality rate for the similar diseases, influenza and pneumonia.  Together, these diseases are coded in the 10th revision of the International Classification of Diseases as J09-J18, and, according to the CDC, the category is the 8th most common cause of death in the U.S.  I downloaded the most recent ten years of data (2007 to 2016) from the CDC mortality website.  On average, influenza/pneumonia was responsible for 53,800 American deaths per year.  The exact number varied, from just over 50,000 in 2010 and 2012, to 57,000 in 2015. 

Covid-19 has been widely reported to pose an elevated risk for older adults.  In this regard it mimics the distribution of influenza/pneumonia.  In the chart above, note that 46% of influenza/pneumonia deaths were in the age group 85+ years, 26% were in 75-84-year-olds, and 13% in 65-74-year-olds.  In other words, a full 85% of deaths from influenza/pneumonia are in the retirement-age population.  These individuals frequently have underlying health conditions that make them more susceptible, or immune systems that are less robust than those of younger people.

However, no age group has complete immunity from influenza/pneumonia.  There are deaths at all ages, even though the numbers get very low.  The second chart below provides a closer look at ages from birth to 44 years.  Note that about as many children under 5 die from influenza/pneumonia as the entire group from 5 to 24 years. 


It will be a couple years before the covid-19 deaths and their distribution are understood in detail.  On March 24, the CDC assigned a new code for these deaths, assuring more accurate tracking.

Covid-19 is an entirely new infection, and the dynamics will not mirror influenza/pneumonia, for which many in our population are at least partly vaccinated.  However, policymakers should recognize that the most susceptible population is 65+ years old.  A question that should be debated: Is it possible to quarantine and protect the elderly while not shutting down the economy, the consequences of which are devastating, most severely for people with marginal incomes and resources?  Intelligent policymaking will require robust data and comprehensive analysis.

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