Deaths from Flu and Pneumonia Jumped Sharply In Recent Years

As the world determines how to approach the spread of the Coronavirus, the disease is regularly compared to seasonal influenza in terms of mortality rate and contagiousness.

In a recent press conference, Nancy Messonnier Director of the Center for Disease Control’s (CDC) National Center for Immunization and Respiratory Diseases compared the agency's response to Coronavirus to that of the flu and the World Health Organization (WHO) released a report detailing the differences between the two.

While the COVID-19 virus has some attributes in common with influenza—they're both respiratory infections with similar symptoms—they have numerous differences, such as severity. Few infected with COVID-19 experience severe symptoms compared to influenza, although the crude mortality rate—the number of reported deaths divided by the reported cases—is higher for COVID-19 than the flu even though the infection mortality rate—the number of reported deaths divided by the number of infections—is lower according to the WHO.

While the world focuses on the Coronavirus, the severity of the flu has had a sharply growing impact in recent years as the number of deaths related to the flu and pneumonia, often a resulting symptom of the flu, spiked since 2010.

In 2010, the CDC lists the number of deaths from influenza and other viruses at only 85. By 2018, it was over 11,000.

Comparatively, the number of deaths due to bacterial pneumonia, something not distinctly associated with viral influenza, has been holding steady between 2,400 and 4,300 deaths per year since 1999.

Conflation with Pneumonia

Mortality statistics due to influenza can be a little fuzzy because of how it is conflated with pneumonia. Most of causes of death related to the flu are from viral pneumonia, but often the cause of viral pneumonia is from the influenza virus, approximately one-third of the time according to the CDC, and the CDC sometimes groups them under the same generalized category for underlying cause of death. But pneumonia can also be bacterial or come from other viral infections that are not influenza. Detailed cause of deaths from the CDC also list pneumonia as over 20 times more frequent than influenza.

So far, the CDC has estimated 20,000–52,000 deaths from influenza from October 1, 2019, through February 29, 2020 alone. But another CDC breakdown of deaths by both pneumonia and influenza lists influenza deaths at around only 4,000 for the 2019-2020 season. For pneumonia, it's over 66,000.

Vaccination Rates

The large growth in flu-related deaths comes despite historically high rates of influenza vaccination. Vaccination rates fluctuate from year to year and by age group, but 2018 recorded a historically high rate of 68.1 percent for those over 65 years of age based on CDC survey data. In 2011 it was 64.9 percent.

While 2018 was a relative high point, 2017 was the nadir of vaccination rates at 59.6 percent for the over-65 cohort, although that year appears to be an abberation as no other substantial drops in vaccination rates occurred otherwise.

Flu-Related Deaths by Age

Deaths due to the flu and pneumonia are highly correlated with age, as 93 percent of all deaths occur to those 55 years or older, and the majority of those occur to those 75 years and older, 74 percent of flu/pneumonia deaths.