The Cause of High Mortality Rates during 1918 Flu Pandemic May Not Be What You Think.

The Spanish influenza pandemic, which began in 1918, caught the world by surprise. No one knows for sure how many people died from the viral outbreak, but researchers from the 1920s estimated that 21.5 million died as a result of the 1918-1919 pandemic. Others estimate that 500 million people worldwide became infected and the virus killed 50 to 100 million of them in three distinct waves. Governments around the world responded in ways that were reactive and mostly ineffective before the pandemic ended in 1919, just as suddenly as it began one year earlier.

High Rates of Mortality

The high case fatality rate, especially among young adults, is not completely understood. Late deaths were attributed to bacterial pneumonia while early deaths in the young were commonly due to “wet lungs” or severe acute respiratory distress syndrome (ARDS). Why was this mortality rate so high?

Case-fatality rates (proportion of deaths amongst people with a medical condition) varied between 0.58% and 10% in army camps with greater than 10,000 cases of influenza or pneumonia. This wide variation in death rates was also observed between cities, some of which were close together and could not be explained by climate, population density, preventive measures, or other environmental characteristics according to an article published on the topic in Clinical Infectious Diseases (CID 2009:49 1 November). These differences in death rates may have been attributed to the improper use of salicylates (aspirin).

Toxic Medicine

According to the article written by Dr. Karen M. Starko, the use of salicylates during the 1918-1919 pandemic resulted in toxicity, which contributed to the incidence and severity of early ARDS, subsequent bacterial infections, and overall mortality. Recently discovered evidence from the time demonstrates that aspirin dosing regimens recommended to adult patients for the “Spanish influenza” were unknowingly at toxic levels that ultimately predisposed patients to severe lung complications. Similar findings were discovered from the 1950s to the 1980s when thousands of children died several days following an influenza illness that was directly attributable to the use of aspirin. Once aspirin warning labels were introduced, this condition (i.e., Reye Syndrome) disappeared.

In conclusion, the high death rates among young adults during the influenza pandemic of 1918-1919 may be directly related to the aspirin regimens recommended during that time especially amongst new army recruits. Varying aspirin use may also be the contributing factor that explains the difference in mortality between cities and between military camps.


Aspirin and 1918-1919 Influenza Mortality; CID 2009:49 (1 November); 1405-1409.

Emerging Infectious Diseases • • Vol. 12, No. 1, January 2006

Spanish Influenza in North America.