A bird flu vaccine for humans that uses only a very low dose of active ingredient has proved effective in clinical tests and could be available next year, its manufacturer, GlaxoSmithKline, claimed yesterday.
While a number of pharmaceutical companies have vaccines against the H5N1 strain of flu in development, GlaxoSmithKline believes its vaccine will work more efficiently than rival ones because of the additives put into it to boost the immune system and make it respond more efficiently.
In addition its vaccine contains just 3.8 micrograms of antigen or active ingredient, yet more than 80 per cent of healthy adult volunteers who received two doses had a strong immune response in clinical trials.
That level of protection meets or exceeds requirements set by regulatory agencies for approving new flu vaccines.
Dr Ronald Cutler, an expert in infectious diseases at the University of East London, said it was good news that this vaccine can produce a significant response from a relatively small dose.
"One of the main problems with previous H5N1 vaccines is that they required a large dose," he said.
Glaxo chief executive Jean-Pierre Garnier said it was a "significant breakthrough. All being well, we expect to make regulatory filings for the vaccine in the coming months."
While Glaxo's vaccine offers protection against the deadly H5N1 avian flu virus now circulating, its impact on any mutated strain of virus is not certain.
However, experts say it could "prime" a person's immune system so they will get stronger effects from a later, better-matched vaccine.
The H5N1 strain of avian influenza has spread rapidly out of Asia and has killed more than 130 people who have come into close contact with infected birds. Experts fear it could trigger a global epidemic of flu that could kill millions, if it acquires the ability to pass easily from human to human.
Other firms working on a bird flu vaccine include Novartis AG, Baxter International Inc and Chiron. (Additional reporting Reuters)