Commentary
Mismatched H5N1 Vaccines Stockpiled By WHO?
Recombinomics Commentary 11:38
June 30, 2008
we acknowledge your statement provided in your submission of April 5, 2007, that Sanofi Pasteur Inc. does not intend to license this product for commercial distribution, since it was produced under contract to the U.S. Department of Health and Human Services as part of national pandemic preparedness initiatives. Influenza Virus Vaccine, H5N1, is indicated for active immunization of persons 18 through 64 years of age at increased risk of exposure to the H5N1 influenza virus subtype contained in the vaccine.
Under this authorization you are approved to manufacture Influenza Virus Vaccine, H5N1 at your Swiftwater, PA facility. Final product filling, labeling, and packaging will be performed at your above facility. The vaccine will be supplied as a suspension in 5 mL multi-dose vials.
The dating period for Influenza Virus Vaccine, H5N1 shall be 18 months from the date of manufacture of the final container vaccine. The date of manufacture shall be defined as the date on which this monovalent vaccine is filled; thus, the 18-month shelf life is inclusive of the time that the product is held in filled final containers at 2-8oC prior to packaging.
The above comments, from the FDA approval letter for a pre-pandemic vaccine, raise questions about the disposition of a mismatched expiring stockpiled vaccine. As indicated, the vaccine was produced under a US HHS contract and therefore is not for distribution. As also indicated, the vaccine has an 18 month shelf life from the manufacture date.
This vaccine was targeted against clade 1 H5N1 from a patient in Vietnam in 2004. The early vaccines have marginal activity against the immunizing target in healthy young adults. The vaccine has limited cross reactivity with clade 2 which is the current clade causing virtually all reported human H5N1 infections. Since most of the vaccines that have gained regulatory approval were developed under programs that began several years ago, virtually all have clade 1 targets, including the US vaccine discussed above, as well as the vaccine in Japan, which is being discussed for use in first responders, which is likely linked to the recent clade 2.3.2 outbreaks in Japan, South Korea, and southeastern Russia. This Fujian strain was isolated from dead whooper swans in northern Japan, raising concerns that the Fujian strain, which is widespread in southern China and southeast Asia, will significant expand its global reach via the east Asian flyway, which links into North America via Alaska.
Recent results however, indicate the clade 1 vaccine can prime the immune response for subsequent booster shots given 1 to 1 ½ years after the initial two shots. Thus, these expiring pre-pandemic vaccines may have utility if used prior to the expiration. Recently, Sanofi Pasteur and GlaxoSmithKline have announce plans to ship 110 million vaccine doses (for vaccination of 55 million people) to the WHO for stockpiling for use after a pandemic begins.
However, the limited shelf life of a pre-pandemic vaccine, coupled with weak activity and significant mismatches, raises serious concerns about the value of such an approach to those who receive the vaccine, or the development of a vaccine against an emerging H5N1 which is being treated with a poorly matched vaccine.
These plans to stockpile weak mismatched vaccines may be hazardous to the world’s health.
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