World moves closer to having bird flu vaccine-WHO

By Richard Waddington

GENEVA, Feb 16 (Reuters) - The world has moved significantly closer to developing vaccines against a bird flu pandemic, but is still not able to make them in the amounts needed, the World Health Organisation (WHO) said on Friday.

Manufacturers in at least three regions, the United States, Europe and Australia, were seeking authority from regulators to be able to produce vaccines for two of the five bird flu strains that have killed humans.

"For the first time, results ... have convincingly demonstrated that vaccination with newly developed avian influenza vaccines can bring about a potentially protective immune response," the WHO said in a statement following a 2-day meeting of experts.

It was the third such meeting in two years as the United Nations health agency spearheads an international campaign to prepare for a possible global outbreak of bird flu in which millions of people could die.

The H5N1 avian flu virus has killed 167 people worldwide since 2003, mainly in Asia. Public health experts fear it could mutate into a form that people catch easily from one another, possibly sparking a pandemic.

"What has been achieved is extraordinary. It is probably unprecedented. The mood has changed dramatically," said professor Ian Gust, an Australian microbiologist who has chaired all three sessions, which are also attended by companies.

"15 months ago, we were not even sure we were going to be able to make a vaccine in any time frame," he told journalists.

Although drugs' companies were working with only two of the killer strains, it was assumed that the process once perfected could apply to any H5N1 virus, Gust said.

Before giving the go ahead, regulators needed to be sure -- and for that they needed plenty of data -- that an influenza vaccine made from an avian virus would behave identically to a vaccine made with the usual, seasonal human virus.

LESS DEFENCELESS

The current strains were found in Hong Kong in 1997, Vietnam in 2004, Eurasia-Africa in 2005-2006, Indonesia in 2005 and Anhui province in China in 2005.

Australian drug manufacturer CSL Ltd. (CSL.AX) has developed a vaccine with a strong immune response against the virus in adults aged 18 to 65, and rival GlaxoSmithKline Plc (GSK.L) has applied to register its own vaccine in Europe following a 80 percent success rate in trials.

Although producing a vaccine for any new strain would still take at least three months from the moment that it was identified, the world was less defenceless, Gust said.

"Should something occur, we are primed to go with a number of these products from a number of manufacturers, and the critical issue will be production capacity," he said.

Manufacturing capacity worldwide for influenza vaccines is currently limited to around one billion doses, which would be insufficient to protect a global population of over 6 billion.

Neverthless, a mix of planned increases in production and signs that the vaccines can become more effective, so reducing the dosage, could combine to narrow the gap.

"Given where we are now, one would expect the gap between what is currently possible and what is desirable ... will continue to be reduced over the next year or two," Gust said.