Swine flu vaccine yields improving, says Glaxo CEO

LONDON (Reuters) - Production yields for H1N1 swine flu vaccine are now increasing and output should reach full throttle in around a month's time, the chief executive of GlaxoSmithKline said on Wednesday.

Major vaccine producers have been struggling with low yields, leading to lower than expected shipments and a scramble for supplies in some markets -- notably the United States.

But Glaxo's Andrew Witty, presenting third-quarter financial results, said things were getting better.

"Yes, yield is improving," he said. "I would expect us to be at full pace by about four weeks or so from now ... the likely final yield is going to be pretty good compared to historic flu strains."

Glaxo is one of the world's largest manufacturers of flu vaccines, along with Sanofi-Aventis and Novartis.

It is not, however, a big source of vaccine for the United States, since its main H1N1 vaccine Pandemrix contains an adjuvant, or additive, and is not being used there.

Glaxo is still awaiting regulatory approval for a non-adjuvanted version of the vaccine for the U.S. market.

"To be honest with you, we are a little bit of a bit-part player in the U.S. flu scenario," Witty said, adding the around 7.5 million doses it expected to deliver were a "tiny fraction" of total U.S. needs.

Worldwide, Glaxo has taken orders for more than 440 million doses of Pandemrix.

(Reporting by Ben Hirschler and Kate Kelland)