It would appear that the recent re-creation of the Spanish flu (“Characterization of the reconstructed 1918 Spanish influenza pandemic virus,” T. M. Tumpey et al. , Research Articles, 7 Oct. 2005, p. 77) could become a case of curiosity killing the cat. Saving the world from a disaster similar to the 1918 epidemic is a noble aim, but the dangers posed by this flu getting out of hand must have crossed the minds of those engaged in the race to re-create the flu (the papers on the characterization and re-creation of the virus were required by the U.S. National Science Advisory Board for Biosecurity to state that the work is important for public health and was conducted safely). Scientists must consider the consequences of this work. Biosecurity experts seem inclined to believe that the risk that the re-created strain might escape is so high, it is almost a certainty ([1][1]). Containment cannot be fail proof; neither can shipment in the mail (as now allowed by CDC and stated to be “very, very safe”) ([2][2]). Regeneration is possible in any well-equipped molecular biology laboratory. Indeed, the Canadians wishing to work with this flu find it less complicated to make it themselves by following the published procedure than to get permission to import it from the United States ([2][2]). The spread of the Spanish flu virus appears more likely and to pose more dire consequences than those conceived for the avian flu virus. Now that the virus has been re-created and has yielded important new information about its virulence factors and high replication efficiency, it may be prudent to use this same information to create a vaccine, given that containment can never be certain. 1. 1.[↵][3]1. J. K. Taubenberger 2. et al. , Nature 437, 889 (2005). [OpenUrl][4][CrossRef][5][PubMed][6][Web of Science][7] 2. 2.[↵][8]1. A. von Bubnoff , Nature 438, 134 (2005). [OpenUrl][9][CrossRef][10][PubMed][11] # Response {#article-title-2} We share Jensenius's belief that the re-creation of the 1918 influenza pandemic virus has yielded important new information about what made this virus so virulent. There is still much to learn about this lethal virus that killed an estimated 50 million people. The recently published findings reveal essential information to speed our preparation for—and potentially thwart—the next influenza pandemic. These new studies provide an immediate impact by helping scientists focus on detecting changes in the evolving H5N1 virus that might make widespread transmission among humans more likely. The findings may lead to identification of new targets for drugs and vaccines to treat and prevent influenza, now and in the future. Although some have been concerned about the re-creation of this historical killer, descendents of the 1918 pandemic virus circulate widely and most people in the world have some immunity. Any risk to the public of accidental release of the 1918 virus is remote. All work was conducted with stringent biosafety and biosecurity precautions designed to protect workers and the public from possible exposure to this virus. CDC has no plans to send the virus outside of CDC. Any requests we do receive will be carefully considered on a case-by-case basis, taking into account scientific merit, biocontainment concerns, and any additional standards deemed appropriate for this particular virus. Understandably, some have questioned whether the findings should have been reported publicly. We are confident about the necessity of this work and the obvious benefits that will continue to be obtained by a robust and responsible research agenda aimed at developing the means to detect, prevent, and treat patients from threats like the 1918 influenza virus. By publishing the results and making them widely available to the scientific community, we encourage additional research at a time when we desperately need to engage the scientific community and accelerate the development of diagnostic assays, treatments, and vaccines to improve our ability to prevent or control pandemic influenza. ![Figure][12] 1918 influenza.CREDITS: (TOP) CYNTHIA GOLDSMITH/PHIL; (BOTTOM) USA LIBRARY OF MEDICINE/SCIENCE PHOTO LIBRARY [1]: #ref-1 [2]: #ref-2 [3]: #xref-ref-1-1 View reference 1. in text [4]: {openurl}?query=rft.jtitle%253DNature%26rft.stitle%253DNature%26rft.aulast%253DTaubenberger%26rft.auinit1%253DJ.%2BK.%26rft.volume%253D437%26rft.issue%253D7060%26rft.spage%253D889%26rft.epage%253D893%26rft.atitle%253DCharacterization%2Bof%2Bthe%2B1918%2Binfluenza%2Bvirus%2Bpolymerase%2Bgenes.%26rft_id%253Dinfo%253Adoi%252F10.1038%252Fnature04230%26rft_id%253Dinfo%253Apmid%252F16208372%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [5]: /lookup/external-ref?access_num=10.1038/nature04230&link_type=DOI [6]: /lookup/external-ref?access_num=16208372&link_type=MED&atom=%2Fsci%2F311%2F5767%2F1552.2.atom [7]: /lookup/external-ref?access_num=000232338600047&link_type=ISI [8]: #xref-ref-2-1 View reference 2. in text [9]: {openurl}?query=rft.jtitle%253DNature%26rft.stitle%253DNature%26rft.aulast%253Dvon%2BBubnoff%26rft.auinit1%253DA.%26rft.volume%253D438%26rft.issue%253D7065%26rft.spage%253D134%26rft.epage%253D135%26rft.atitle%253DDeadly%2Bflu%2Bvirus%2Bcan%2Bbe%2Bsent%2Bthrough%2Bthe%2Bmail.%26rft_id%253Dinfo%253Adoi%252F10.1038%252F438134a%26rft_id%253Dinfo%253Apmid%252F16280992%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [10]: /lookup/external-ref?access_num=10.1038/438134a&link_type=DOI [11]: /lookup/external-ref?access_num=16280992&link_type=MED&atom=%2Fsci%2F311%2F5767%2F1552.2.atom [12]: pending:yes