Although no final decision has been made to produce a vaccine against the new strain of swine flu, officials at the World Health Organization say they are aware of “preproduction contracts” by wealthy countries that may lay claim to substantial quantities of any that is made.

The worldwide capacity for making a pandemic vaccine is 2 billion doses at the most and possibly as few as 1 billion doses, depending on the uncertainties involving production and dosage. Of that total, the United States has pre-existing contracts allowing it to buy at least 600 million doses.

” ‘Claim’ is a hard word for me to swallow,” said Robin Robinson, head of the Biomedical Advanced Research and Development Authority of the Department of Health and Human Services, responsible for much of the nuts-and-bolts planning for a flu pandemic in the United States.

“We have the contractual mechanisms to purchase pandemic or other influenza vaccines,” Robinson said last week. “We believe the U.S. needs could be satisfied by the capacity that is out there from these contracts.”

Robinson said HHS orders could go as high as two doses of vaccine for the entire U.S. population of about 305 million. Two shots may be needed to stimulate immunity against the newly emerged swine-origin H1N1 strain.

The contracts are with Sanofi Pasteur, GlaxoSmithKline and Novartis, all of which make the traditional flu-shot vaccine, which takes four to six months. HHS has a contract with MedImmune, which makes smaller amounts of vaccine a different way.