Jill Wechsler
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A small but rising number of deaths from avian flu in Asia is prompting health experts to predict a global flu pandemic in
the next few years. The World Health Organization (WHO) warns that the avian flu virus is likely to mutate and spread to humans,
which could potentially kill millions worldwide and stress health care systems, as well as the international capacity to produce
needed vaccines and medicines.
At home, the Department of Health and Human Services (HHS) is developing a Pandemic Influenza Preparedness and Response Plan,
issued in draft form last August. Members of Congress now want a final plan and evidence of progress in developing vaccines
and treatments to cope with a major flu pandemic. Coming in the wake of last year's devastating flu vaccine shortage, plus
regular supply problems with routine children's vaccines, policymakers are very nervous about how the nation will deal with
a global health crisis.
FRAGILE SYSTEM
In preparing for a serious flu outbreak, an important challenge is to ensure an adequate and timely supply of influenza vaccine,
according to Congress' Government Accountability Office (GAO), [GAO-05-760T, May 26, 2005]. However, US preparedness efforts
are hampered by a lack of domestic vaccine manufacturing capacity. Only five manufacturers produce vaccines for the US market,
and only one company makes conventional seasonal flu vaccine entirely in the US. At a hearing on pandemic flu preparedness
before the House Energy and Commerce Committee in May, Julie Gerberding, director of the Centers for Disease Control and Prevention
(CDC), described the US vaccine manufacturing system as "fragile." She noted that pandemic flu vaccine produced in other countries
probably will not be available in the US because other governments "may prohibit export of the vaccines produced in their
countries until their domestic needs are met."
The National Institutes of Health (NIH) are supporting research efforts geared toward new vaccine production methods as well
as disease analysis. FDA is developing policies to facilitate new vaccine approval and ensure that manufacturing facilities
meet all quality standards. While vaccine manufacturing is a tricky business in any situation, fast production of a vaccine
for a novel virulent influenza strain raises additional challenges. It now takes six to eight months to identify prevalent
flu strains each season, to develop effective vaccines, and to ramp up production of millions of doses.
Policy makers recognize that efforts to expand the nation's vaccine manufacturing infrastructure and to stabilize the market
for routine and seasonal vaccines will lay a foundation for responding to a national or global pandemic. Last year's shortages,
to some extent, may help improve the process by boosting funding for new programs and removing regulatory and legal obstacles
to vaccine development. A number of NIH and CDC initiatives have been launched that support vaccine R&D and expanded production
capacity:
- Improved egg production methods. Sanofi-Pasteur (Swiftwater, PA) has a five-year $40 million contract with HHS to provide
a secure, year-round supply of eggs suitable for full capacity flu vaccine production.
- Development of cell-based vaccine production methods that eliminate the need for eggs altogether to produce other vaccines
in the US and Europe. HHS seeks proposals from additional manufacturers to test cellular and recombinant vaccines and has
awarded Sanofi-Pasteur a grant in this area.
- Support for new vaccine production facilities. Sanofi has committed to expand its current manufacturing operation to produce
up to 300 million doses of monovalent pandemic vaccine, a process that will take at least five years.
- Improved vaccine manufacturing processes at existing facilities. HHS offers funding for manufacturers to develop more efficient
methods for viral master seed production; egg inoculation; growing, purifying and harvesting vaccine; formulating the vaccine
product; and loading vials or syringes.
- Development of dose-stretching strategies that decrease the amount of flu virus antigen needed in each dose, such as adding
an adjuvant to a formulation to stimulate immune response.
- Pilot testing of pandemic flu manufacturing capacity. Under a contract with the National Institute of Allergy and Infectious
Diseases (NIAID), Sanofi-Pasteur produced pilot lots of a new H5N1 vaccine for testing in clinical trials. Even before obtaining
study results, Sanofi will produce two million doses of the vaccine to ensure satisfactory large-scale manufacturing and
production techniques and conditions.
