Continued Steps toward H1N1 Vaccine
The United States Department of Health and Human Services (HHS) is trying to cover all of its bases as it seeks to stockpile a vaccine to fight influenza A (H1N1). GSK and Sanofi are first on the list of drugmakers that will work with HHS to meet its objectives. Research scientists are also preparing for possible drug-resistant strains by making progress toward a new type of drug that will be able to stop the spread of infection and possibly prevent initial infection.
In accordance to an existing contract, HHS has placed an initial order, valued at $190 million, with Sanofi Pasteur for a vaccine. The order provides for the production of the bulk vaccine. However, the company is still awaiting the seed virus from the US Centers for Disease Control. Once the seed virus is obtained, the company says it will have a better timeline of when the vaccine might be available. Moreover, dosage requirements have not yet been determined and the final formulation, filling, and distribution of the vaccine have not yet been established. Sanofi Pasteur also says it “is prepared to commence commercial scale production in June following certification of the working seed by the US Food and Drug Administration.”
Meanwhile, HHS has also placed initial orders for influenza A (H1N1) antigen from GSK as well as the company’s proprietary AS03 adjuvant system, which the company already used in phase II trials of an adjuvanted influenza A H5N1 (avian flu) vaccine. According to a May 15 release, GSK says it is also waiting on a seed virus from the World Health Organization. The company claims it has also received “several orders from several governments” for an influenza A (H1N1) adjuvanted vaccine. The governments of France, Finland, Belgium, and the United Kingdom were listed in this release.
Perhaps future vaccine production will take a completely different approach. In a previous post, I questioned what would happen if the H1N1 virus became resistant to current antiviral drugs. Evidently, a team of researchers is already on their way to solving that potential problem. At Rensselaer Polytechnic Institute in Troy, NY, work is underway to test a new approach for combating the influenza A virus, including its possible mutations. In an announcement made May 19, scientists said they are seeing “promising preliminary results” of a chemical approach to targeting both the hemagglutinin (H) and neraminidase (N) outer protein components of the influenza A virus. Current influenza drugs target only the N portion, which disrupts the ability of the virus to leave an infected cell and infect other healthy cells. The new approach, based on “click chemistry,” targets the H protein, which prohibits entry into the healthy cell. The research team says they can manipulate the chemistry to target one or both components depending on the mutation (e.g., H1N1 associated with swine flu or H5N1 associated with avian flu).
The best treatment for influenza infections in humans is prevention by vaccination. Work by several laboratories has recently produced vaccines. The first vaccine released in early October 2009 was a nasal spray vaccine. It is approved for use in healthy individuals ages 2 through 49. This vaccine consists of a live attenuated H1N1 virus and should not be used in anyone who is pregnant or immunocompromised. The injectable vaccine, made from killed H1N1, became available in the second week of October. This vaccine is approved for use in ages 6 months to the elderly, including pregnant females. Both of these vaccines have been approved by the CDC only after they had conducted clinical trials to prove that the vaccines were safe and effective. However, caregivers should be aware of the vaccine guidelines that come with the vaccines, as occasionally, the guidelines change. Please see the sections below titled “Can novel H1N1 swine flu be prevented with a vaccine?” and the timeline update for the current information on the vaccines.