Bacterial Pneumonia Found to be a Major Cause of Death in Flu Pandemic

From University of Pittsburgh Medical Center
By Matthew Watson, August 4, 2008

The August issue of Emerging Infectious Diseases (EID) includes two articles on the impact and implications of bacterial co-infection, and resulting pneumonia in influenza patients, during a pandemic.

Authored by Dr. John Brundage and Dr. Dennis Shanks, the first article is a retrospective epidemiological review that analyzes the unusual nature and severity of the 1918–19 influenza pandemic.1 Dr. Brundage’s claim is that the high case fatality rates seen during that pandemic were not due, as some historians have claimed, to primary pneumonia caused by a hypervirulant strain of the influenza virus. Rather, he maintains that many of the deaths that occurred during the 1918 pandemic resulted from co-infection and subsequent pneumonia caused by common respiratory bacteria.

The second article, authored by Gupta, et al., identifies bacterial pneumonia as a likely source of mortality during a pandemic and offers recommendations for addressing gaps in medical pandemic preparedness. While acknowledging the scarcity of recent data regarding the incidence of bacterial co-infection during a pandemic, Gupta notes that “secondary bacterial infection is a common cause of death in persons with seasonal influenza; co-infections have been found with ≈25% of all influenza related deaths.”2

Both Brundage and Gupta agree that the pathogens most likely to cause respiratory disease are Streptococcus pneumoniae, Staphyloccus aureus (both methicillin sensitive and resistant3) and Haemophilus influenza. Accordingly, the use of antimicrobial medications effective against these pathogens will be indicated—for either treatment or prophylaxis. However, due to the use of “just in time” supply chains, pharmaceutical shortages are likely. Consequently, both authors recommend that hospitals work with suppliers on stockpiling efforts in order to mitigate shortages.

The two papers also generally agree on the following recommendations aimed at reduction of mortality due to bacterial pneumonia for influenza patients in a pandemic:

To the extent possible, make vaccination against S. pneumoniae a priority prior to a pandemic event.
Once a pandemic has begun, vaccinate communities that are still unaffected with a strain-specific influenza vaccine, if available.

During a pandemic, isolate patients with symptomatic respiratory disease as much as possible.
Conduct surveillance to track pandemic-related bacterial infections and emerging antimicrobial resistance.
Conduct further research into bacterial pneumonias that occur secondary to influenza infection.


Brundage JF, Shanks GD. Deaths from bacterial pneumonia during 1918-19 influenza pandemic. Emerg Infect Dis. 2008;14:1193-1199. Accessed July 24 2008.
Gupta RK, George R, Nguyen-Van-Tam JS. Bacterial pneumonia and pandemic influenza planning. Emerg Infect Dis. 2008;14:1187-1192. Accessed July 24 2008.
The Centers for Disease Control and Prevention. Severe methicillin-resistant Staphylococcus aureus community-acquired pneumonia associated with influenza—Louisiana and Georgia, December 2006–January 2007. MMWR. 2007;56:325-9. Accessed July 24, 2008.