April 28, 2005
Oseltamivir (commercial trade name “Tamiflu”) is an antiviral drug licensed by the Food and Drug Administration (FDA) for the prevention and treatment of influenza A and B. On April 26 the Washington Post editorial page carried an article titled “Flu Prevention” in which it was stated that the USA has fallen behind other countries in stockpiling oseltamivir for potential use against the H5N1 influenza virus that may trigger the next flu pandemic.
This high-visibility involvement in influenza pandemic preparedness by a major US newspaper could be a catalyst to accelerate action to mitigate what will be an acute international health crisis when this pandemic occurs. The Post and other major print and electronic media could contribute more to global preparedness by publishing at regular intervals updates on pandemic influenza preparedness (or lack thereof) based on the weekly-monthly updates from international sources, the World Health Organization (WHO), and the US Department of Health and Human Services, including the CDC, NIH, and FDA. Such updates would form a “Pandemic Watch” that could serve to enhance pandemic preparedness and prevent the pandemic panic that is likely to occur with this respiratory disease starts to spread from person-to-person.
The Post compares Britain’s purchase of 15 million courses of this drug, enough for one-quarter of their population, with the purchase of only 2.3 million doses by the USA. The editorial page goes on to state “A part of the problem may also be overall reluctance in Washington to recognize the danger that a flu epidemic poses.” They contrast this lack of a large stockpile of oseltamivir with the “U.S. government’s early recognition of the danger and its investment in vaccines” against the H5N1 virus and the “almost daily reports” on the spread of this virus in Asia, (by the WHO and other sources).
The Post acknowledges that “U.S. officials point out that the drug is not perfect”, but the media would provide a service to the population-at-large by additional articles, part of a “Pandemic Watch” type educational campaign about pandemic influenza by delineating some of the potential problems with oseltamivir. For example, the drug is much more costly that older anti-influenza drugs such as amantadine and rimantadine, but the H5N1 virus now in Asia is resistant to these latter two drugs. Indeed, this H5N1 virus, or its pandemic-causing descendants will predictably develop some degree of resistance to oseltamivir.
For now, however, oseltamivir is the only anti-influenza drug that can be taken by mouth that is proven to kill the H5N1 virus in laboratory tests. A clinical study has not yet been done to answer how effective oseltamivir is at preventing or treating H5N1 infection. Such a study needs to be designed and ready for implementation long before the first major outbreaks of the early pandemic, a hard-learned lesson from the SARS outbreak of 2003.
Another issue with oseltamivir is that for prevention (“prophylaxis”) the drug is not approved for children ages 1-12 years. And the dose of this drug varies by weight for the treatment of children 1-12 years of age who are already ill. Thus, a liquid suspension is needed for children as well as capsules for persons 13 years of age and older. In this regard the shelf life of oseltamivir capsules is relatively long, namely 4 years (48 months), while the shelf life of the oral suspension (as a dry powder) is 18 months, according to an announcement January 6, 2004 by the European-based drug manufacturer, Roche Laboratories.
Daniel R. Lucey, MD, MPH
Director, Center for Biologic Counterterrorism and Emerging Diseases, Washington Hospital Center
Adjunct Professor, Department of Microbiology and Immunology
Georgetown University School of Medicine