New Bird Flu Vaccine Effective

August 1, 2006

New Bird Flu Vaccine Effective

Pharmaceutical company GlaxoSmithKline (GSK) has developed a new vaccine against H5N1 bird-flu virus that appears to be more effective other vaccines – and requires a much smaller dose“ according to a recent study.

As the threat of a bird-flu pandemic continues, countries around the world have been stockpiling Roche’s Tamiflu, until now considered the most effective drug for combating the disease. However, concerns have persisted about the availability of sufficient quantities of the vaccine, in case of a pandemic.

Because GKS’s new vaccine appears to be effective in much smaller doses, it increases the likelihood of being able to immunize large numbers of people, in the case of a global pandemic.

Comparison of Vaccines

With the possibility of a global pandemic looming, it is unsurprising that several drug companies are trying to develop vaccines to combat the H5N1 bird-flu virus.

Results of a study in 2006 showed that a vaccine made by Sanofi Pasteur was effective. However, the required dose was too high to make it a reasonable alternative in a pandemic, according to the International Herald Tribune.

The GlaxoSmithKline vaccine was tested on 400 healthy people, aged 18-60 years. Participants underwent blood tests to measure the response of their immune system to the vaccine. More than 80% of participants were protected by two shots of 3.8 micrograms of antigen each.

In contrast, the Sanofi Pasteur vaccine offered protection to only about 50% of the study-participants, according to The International Herald Tribune. Moreover, these participants received substantially higher doses of antigen (90 micrograms each), making it a more costly drug to produce.

Although the GSK vaccine is not yet available, GSK anticipates seeking FDA approval this year. Paul Richards, an FDA spokesman, reportedly said, "We are encouraged by GSK’s promising report," adding that the vaccine would likely be accepted for accelerated approval – in as little as in six months.

The GSK vaccine would be priced at the same level as a standard flu-shot, said Patty Seif, a GSK spokeswoman – that is, about $8-12 per shot, according the International Herald Tribune.

Importantly, the GSK vaccine includes an adjuvant – a chemical that magnifies the protective effects of the vaccine, making it effective in smaller doses.

The Vaccine’s Effectiveness

The GSK findings are "very, very impressive," according to Dr Anthony S Fauci, director of the National Institute of Allergy and Infectious Diseases, said the International Herald Tribune. However, Dr Fauci warned that the encouraging results were not based on real-life exposure, but only on blood-tests.

"The proof of the pudding is how does it work in the field," Dr Fauci reportedly said, adding that in the case of the virus mutating, the vaccine’s effectiveness is unknown.

GSK’s production capacity for seasonal flu vaccine is 60- 70 million doses annually, and the company is capable of producing the same amount of its bird-flu vaccine, David Stout, president for worldwide pharmaceuticals, reportedly said. By 2008, GSK expects to raise production capacity to 150 million doses annually.

Sources:
GSK reports significant advance in H5N1 pandemic flu vaccine programme, gsk.com, July 26, 2006.
Maker calls new bird flu vaccine more effective, International Herald Tribune, Asia-Pacific, July 26, 2006.
Bird Flu Vaccine Shows Promise, Sanofi-Pasteur, Medical News Today, December 15, 2005.

Posted: August 2006


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