US: A/H1N1 flu vaccine expected to be available in Oct.

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Health officials in the US say they may have over 160 million doses of the A/H1N1 flu vaccine available sometime in October.

Tom Cahill (R) of New York gets his flu shot from a nurse in 2006 at O'Hare Airport in Chicago, Illinois.(AFP/File/Jeff Haynes)

They also predict the country will face a surge in influenza cases later this year.

As the A/H1N1 virus spreads, attention is now shifting to the process of flu vaccine production.

Scientific advisers from the US Food and Drug Administration say they have succeeded to a degree.

They expect to have 160 million doses of A/H1N1 flu vaccine available sometime in October - if all goes well.

The chief ingredient for the vaccine is grown in chicken eggs, but companies are getting far fewer doses per egg than is usual with regular winter flu.

Scientists also expect people will need two separate inoculations, about a month apart, for protection.