New bird flu vaccine has 80% protection rate

Jul 26 2006

According to the manufacturer the latest bird flu vaccine is more than 80% effective in protecting people against the virus.

GlaxoSmithkline says it's vaccine which was produced from an inactivated H5N1 virus and a new adjuvant, uses a lower dose of antigen.

When it was used in healthy adult volunteers it produced a stronger seroprotective immune response than expected by regulatory agencies for influenza vaccine registrations.

The trial took place in Belgium and involved 400 healthy adults aged 18-60 and each participant was vaccinated twice during the trial.

Four levels of antigen were tested with 3.8µg being the lowest dose tested.

As many as thirty companies worldwide are racing to produce a vaccine which will offer protection from bird flu and governments are eager to stockpile vaccine in readiness for a potential pandemic.

The challenge has been how to make the maximum number of shots from the minimum amount of antigen, as if a lower dose is needed, more people can be given the shot.

Antigen is produced in chicken eggs and is a lengthy and arduous process; it boosts the vaccine's effectiveness and makes it more powerful.

GlaxoSmithkline is Europe's biggest pharmaceutical company and says is on track to start manufacturing by the end of 2006 and if approval is granted could mass produce the vaccine in 2007.

The company says the results represent a significant breakthrough and is the first time such a low dose of H5N1 antigen has been able to stimulate such a level of strong immune response.

The vaccine is expected to cost the same as a conventional flu shot, around U.S.$7 and Glaxo is apparently already talking to groups such as the Bill & Melinda Gates Foundation and the Global Fund to Fight AIDS, TB and Malaria with regard to making the vaccine available in poor countries.

Even though Glaxo's vaccine appears to offer protection against the lethal H5N1 avian flu virus currently circulating, whether it will have any impact on any mutated strains of the virus is uncertain and this is something the company is investigating.

The H5N1 strain of avian influenza which first appeared in Asia in 2003 has spread rapidly across the globe and has killed more than 130 people to date.

The virus remains essentially a disease of birds and is only contracted by close contact with infected birds.

Nevertheless experts worry any mutation of the virus could enable it to pass between humans and trigger a pandemic that could kill millions.