The majority of deaths during the influenza pandemic of 1918-1919 were not caused by the influenza virus acting alone, report researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. Instead, most victims succumbed to bacterial pneumonia following influenza virus infection. The pneumonia was caused when bacteria that normally inhabit the nose and throat invaded the lungs along a pathway created when the virus destroyed the cells that line the bronchial tubes and lungs.
The work presents complementary lines of evidence from the fields of pathology and history of medicine to support this conclusion. “The weight of evidence we examined from both historical and modern analyses of the 1918 influenza pandemic favors a scenario in which viral damage followed by bacterial pneumonia led to the vast majority of deaths,” says co-author NIAID Director Anthony S. Fauci, M.D. “In essence, the virus landed the first blow while bacteria delivered the knockout punch.”Bacterial Pneumonia Caused Most Deaths in 1918 Influenza Pandemic, August 19, 2008 News Release – National Institutes of Health (NIH)