Statement

March 6, 2006

Statement by Mike Leavitt, Secretary of Health and Human Services, Regarding Second Strain of the H5N1 Virus

All influenza viruses evolve, or "drift" genetically over time. Changes in the strains of common or seasonal influenza are carefully monitored, and each year vaccine manufacturers develop and produce updated vaccines based on these changes to ensure that the most current vaccines provide maximum possible immune protection.

Just like the seasonal strains of flu, the H5N1 strain also has evolved, and a second distinct version of H5N1 now exists. This strain is now circulating in Europe, Africa and parts of Asia.

Working with industry, HHS has already created a vaccine for the first isolated version of the H5N1 virus. This vaccine has been tested in people and shown to provide an immune response that is predictive of protection, albeit at a very high vaccine dose. HHS has contracted with two companies to manufacture nearly 8 million doses of this vaccine for the Strategic National Stockpile.

Because the second distinct variation of the H5N1 strain has evolved, it is necessary to begin development of a second H5N1 candidate vaccine. The Centers for Disease Control and Prevention (CDC) has already taken the first step by producing the reference virus that will serve as the seed from which a second vaccine might be developed in collaboration with our industrial partners. Upon production of pilot lots of this vaccine, the National Institutes of Health (NIH) will perform clinical testing of the vaccine similar to that with the first H5N1 vaccine.

It is probable that H5N1 will continue to evolve, producing even more viruses with pandemic potential and making it necessary to develop a series of vaccines. There is simply no way to predict which strain, if any, might produce a virus capable of mass human-to-human transmission.

For more remarks by Secretary Leavitt on influenza vaccines, including vaccines for the H5N1 virus, go to: http://www.hhs.gov/news/speech/2006/060306.html

For additional information on the vaccine selection process, go to: http://www.cdc.gov/flu/about/qa/fluvaccine.htm

Last revised: March 7, 2006

The White House | USA.gov | HHS Archive | No FEAR Act