Government efforts to prepare for a modern day influenza pandemic should include a stockpile of antibiotics because bacteria, not the flu virus, were the real killers in 1918, researchers say.

John Brundage, a medical microbiologist at the Armed Forces Health Surveillance Center in Silver Spring, Md., has concluded that the majority of 20 to 100 million victims of the 1918-1919 Spanish flu outbreak actually died from pneumonia, the British magazine New Scientist reported.

The team came to its conclusion after combing through first-hand accounts, medical records and infection patterns from 1918 and 1919.

Furthermore, a journal article from researchers with the National Institute of Allergy and Infectious Disease (NIAID) in Bethesda, Md., set to be released next month, reaches the same conclusion.

"We agree completely that bacterial pneumonia played a major role in the mortality of the 1918 pandemic," Anthony Fauci, author of next month's article and NIAID director, told New Scientist.

Although pneumonia was behind the majority of deaths, it was the "lethal" flu strain of 1918 that allowed pneumonia into the body, according to Jonathan McCullers, an expert on influenza-bacteria co-infections at St Jude Children's Research Hospital in Memphis, Tenn.

"The 1918 pandemic is considered to be — and clearly is — something unique, and it's widely understood to be the most lethal natural event that has occurred in recent human history," Brundage added.

McCullers' research found that influenza kills cells in the respiratory tract, providing food and shelter for bacteria. Additionally, a weakened immune system makes it easier for the bacteria to gain a foothold in the body.

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