Researchers Reconstruct 1918 Pandemic Influenza Virus; Effort Designed To Advance Preparedness

“This groundbreaking research helps unlock the mystery of the 1918flu pandemic and is critically important in our efforts to prepare forpandemic influenza,” said CDC Director Dr. Julie Gerberding. “We needto know much more about pandemic influenza viruses. Research such asthis helps us understand what makes some influenza viruses more harmfulthan others. It also provides us information that may help us identify,early on, influenza viruses that could cause a pandemic.”

The work, done in collaboration with Mount Sinai School of Medicine,the Armed Forces Institute of Pathology and Southeast Poultry ResearchLaboratory, determined the set of genes in the 1918 virus that made itso harmful. Prior to this study, which is published in the Oct. 7 issueof Science, flu experts had little knowledge of what made the 1918pandemic so much more deadly than the 1957 and 1968 pandemics. Thisweek’s issue of Nature also includes a related article entitled“Characterization of the 1918 influenza virus polymerase genes” whichdescribes the final three gene sequences of the 1918 influenza virus.The work reported in the Nature article was done by scientists at theArmed Forces Institute of Pathology.

The 1918 pandemic killed an estimated 20-50 million peopleworldwide, including 675,000 in the United States. The pandemic’s moststriking feature was its unusually high death rate among otherwisehealthy people aged 15-34. During normal seasonal flu outbreaks, severecomplications and death are most common among the elderly and youngchildren.

Influenza pandemics occur when a new strain emerges to which peoplehave little or no immunity. Most experts believe another pandemic willoccur, but it is impossible to predict which strain will emerge as thenext pandemic strain, when it will occur or how severe it will be.

“By identifying the characteristics that made the 1918 influenzavirus so harmful, we have information that will help us develop newvaccines and treatments,” said Dr. Terrence Tumpey, the CDC seniormicrobiologist who recreated the virus. “Influenza viruses areconstantly evolving, and that means our science needs to evolve if wewant to protect as many people as possible from pandemic influenza.”

In reconstructing the 1918 influenza virus, researchers learnedwhich genes were responsible for making the virus so harmful. This isan important advance for preparedness efforts because knowing whichgenes are responsible for causing severe illness helps scientistsdevelop new drugs and vaccines (e.g., they can focus their research onthose genes).

CDC employed stringent biosafety and biosecurity precautions duringresearch on the 1918 influenza virus. The work was done in a highcontainment Biosafety Level 3 lab with enhancements that includespecial provisions to protect both laboratory workers and the publicfrom exposure to the virus. Currently available antiviral drugs havebeen shown to be effective against influenza viruses similar to the1918 influenza virus.

All laboratory work was conducted at CDC. The work was supported inpart with funding from the U.S. Department of Agriculture and theNational Institutes of Health.

To evaluate the benefits of publishing the information contained inthese manuscripts and any potential threat from its possible deliberatemisuse, both manuscripts were reviewed by the National Science AdvisoryBoard on Biosecurity (NSABB). The NSABB advises the federal governmenton strategies for the conduct and communication of research that mightyield information or technologies that could be misused to threatenpublic health or national security. The Board was unanimous in itsdetermination that it was critically important to make these findingsavailable to the scientific community at large to not only validatetheir significance, but also permit further research on the developmentof diagnostic tests, treatments, and preventative measures.

For a joint statement from Dr. Anthony Fauci, director of theNational Institute of Allergy and Infectious Diseases at the NationalInstitutes of Health and Dr. Julie Gerberding, director of CDC, pleasevisit http://www3.niaid.nih.gov/news/newsreleases/2005/0510state.htm.