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NATURE|Vol 435|26 May 2005 AVIAN FLU COMMENTARY ALEX WONG/GETTY IMAGES WONG/GETTY ALEX Race against time A committed, transparent research effort into the detection, prevention and treatment of bird flu is now critical. Anthony S. Fauci presents the questions that need answers. he emergence of the highly pathogenic Influenza Preparedness and Response Plan for genomes, 4 complete H2N2 genomes, 4 com- H5N1 influenza A virus in southeast the fiscal year 2005. Within the HHS, the Cen- plete H7N3 genomes and 30 complete H9N2 TAsia is a grim reminder of the deadly toll ters for Disease Control and Prevention (CDC) genomes (see www.ncbi.nlm.nih.gov/genomes of flu pandemics throughout the ages. This has the key role of mediating disease surveil- /FLU/FLU.html). These data are invaluable virus has the potential to trigger the next pan- lance and the public-health response. In addi- for tracking viral evolution and transmission, demic, which, judging from history, is well tion, the National Institutes of Health (NIH) and for developing new drugs, vaccines and overdue. We cannot predict exactly when a conducts basic research on viral pathogenicity diagnostics. pandemic will occur, nor can we know for cer- and molecular evolution. The NIH also carries Adding to our understanding of the molec- tain whether the culprit will be H5N1 or a out research to identify drug targets and new ular mechanisms driving flu virus emergence related virus. The only certainty is that it will technologies for vaccine production, as well as in animals and their spread to humans is a pro- present extraordinary challenges. Many indi- clinical research to test the safety and efficacy ject carried out by investigators from St. Jude viduals, research and health organizations, and of new diagnostics, vaccines and antivirals (see Children’s Research Hospital, Tennessee. These countries have delineated surveillance goals, www2.niaid.nih.gov/Newsroom/FocusOn/Flu researchers traced the current H5N1 outbreak are sharing information and reagents, and are 04). The NIH’s flu research budget for 2005 is in Asia back through a series of genetic re- asking the multiple research and logistical approximately $119 million; it supports work assortment events to a human outbreak that questions needed to develop an appropriate that complements the efforts of the CDC and occurred in Hong Kong in 1997 (ref. 1). The response. Clearly, there is much to be accom- the Food and Drug Administration (FDA). genetic reassortments resulted in a dominant plished, and time is of the essence. H5N1 genotype infecting chickens and ducks To prepare for and minimize the impact of Watch and learn in 2003 and 2004. Domestic ducks in southern avian viruses with pandemic potential, a mul- A timely response to a potential flu pandemic China were central players in the generation tifaceted approach is essential. This includes a requires diligent surveillance as well as an and maintenance of the virus, with migratory robust, sustained commitment to the research understanding of how flu viruses evolve, birds possibly contributing to the spread of the needed to develop new tools and strategies for spread and cause disease. The NIH Influenza virus throughout southeast Asia. influenza detection, surveillance, prevention Genome Sequencing Project aims to provide It is crucial to continue surveillance studies of and therapy. complete sequence data for selected human this type in order to monitor the spread of flu Preparedness for pandemic flu is a global and avian influenza isolates. When the project viruses from animal to animal, animal to human endeavour, with the World Health Organiza- began in November 2004, only seven human and from human to human. If a virus acquires tion (WHO) playing a pivotal role. The US influenza H3N2 isolates had been completely the ability to transmit efficiently among humans, contribution to the global effort involves sev- sequenced and deposited in the NIH’s Gen- a pandemic is likely, whereupon aggressive eral government agencies that operate in part- Bank database. Six months later, the sequences intervention measures will be needed. nership with private industry and academic of 150 human H3N2 isolates had been deter- Vaccination and the use of antivirals are two institutions. One of the main agencies, the mined and made available. Information now of the most important response measures to a Department of Health and Human Services deposited in GenBank from various sources flu pandemic. H5N1 viruses are sensitive to the (HHS), will spend about $419 million in its includes sequences of 110 complete H5N1 neuraminidase inhibitors oseltamivir (an oral 423 © 2005Nature PublishingGroup AVIAN FLU COMMENTARY NATURE|Vol 435|26 May 2005 drug) and zanamavir (an inhalable powder). In addition, NIH-supported researchers and The HHS and the CDC have created an initial others are attempting the difficult challenge of stockpile of 2.3 million treatment courses of developing a flu vaccine based on antigens that oseltamivir, to which more doses will be added. are conserved across several influenza A More research and discussion are needed to strains. Such a vaccine could be more broadly prioritize the distribution of stockpiled anti- protective against whatever strain an individ- influenza drugs in case of a pandemic. ual might encounter5. The NIH currently funds projects to Prophylactic vaccination with ‘prototype’ develop and test other flu inhibitors, includ- antigens might provide partial protection ing CS-8958, a long-acting next-generation against a pandemic strain6. This concept has neuraminidase inhibitor. Other studies are been referred to as ‘pre-priming’,ROCHESTER OF and may offerSULLIVAN/UNIVERSITY VINCE directed towards identifying and evaluating a way to integrate seasonal flu preparedness new viral drug targets. with pandemic flu preparedness by adding a fourth strain, such as an H5 or H7 subtype, to Ramping up vaccines the familiar annual trivalent flu vaccine. Of Controlling an emerging flu pandemic will course, these ideas are exploratory and prelim- require a rapid and aggressive response: con- inary; studies and discussion are essential to dis- siderable efforts are being channelled into cern whether this approach makes sense from finding ways to streamline vaccine manufac- scientific, safety and logistical perspectives. ture to allow for greater flexibility and surge capacity. The first step in vaccine preparation Fragile enterprise requires the generation of a ‘reference virus’ — Strong collaborations between governments, generally a time-consuming process. A new academic institutions, and industry are needed technique called reverse genetics can be used Protective potion: research into vaccines is to ensure a reliable vaccine supply. At present, to generate, relatively quickly, reference viruses urgently needed to deal with a flu pandemic. pharmaceutical companies are reluctant to that precisely match a target flu strain2. Using enter or remain in the business of manu- this technique, an H5N1 reference virus was more robust than those triggered by inacti- facturing vaccines — unpredictable consumer produced within weeks and used to develop an vated vaccines, such as those described above; demands and lack of financial incentives make inactivated H5N1 vaccine. A phase I clinical they also tend to be more cross-protective vaccine manufacture a risky business. The bio- trial is currently under way to test the safety, against related variants of the same virus4. Live- medical research community can help by immunogenicity (ability to stimulate an attenuated H9N2 and H5N1 vaccine candi- developing state-of-the-art technologies. These immune response), and appropriate dosage dates have been generated and their safety, should be shared with industry to streamline of an inactivated H5N1 vaccine manufactured infectivity and immunogenicity will be tested the manufacturing process and make it more by Sanofi Pasteur. The first phase of the trial in phase I clinical trials, probably later this year. flexible, predictable and able to adapt to evolv- will enroll 450 healthy adults, aged 18 to 64 All licensed flu vaccines rely on the tradi- ing viruses. Financial and economic incentives years, at three sites in the United States. If the tional method of vaccine production: the virus (including fair pricing, guaranteed purchase of vaccine is shown to be safe, it will be tested in is grown inside chicken eggs. But this method unsold supplies, tax incentives, a streamlining the elderly and in children (see www2. does not readily allow for adjustments to of the complex regulatory processes needed for niaid.nih.gov/Newsroom/FocusOn/Flu04/). increase output or to change the formulation for vaccine licensure, liability protection), and a The HHS has awarded a contract to Sanofi a newly emerging virus. The HHS and other vigorous public education effort are under Pasteur to produce 2 million doses of inacti- organizations worldwide are supporting efforts consideration to ensure a steady supply and vated H5N1 vaccine to create a stockpile as part to develop cell-culture methods for vaccine pro- demand for vaccines. of the HHS influenza preparedness plan. This duction. Replacing the traditional method, and The evolving situation in Asia offers an effort will ensure that, should the need arise, the providing the capacity for rapid scale-up, could unprecedented opportunity to prepare for avian manufacturing techniques, procedures, and allow vaccine manufacturers to keep pace with viruses with pandemic