The company whose contaminated plant touched off last year's flu vaccine shortage said yesterday that it won't be able to make all the doses promised for the 2005-2006 influenza season, raising the possibility of another vaccine shortage this fall.

California-based Chiron Corp. blamed manufacturing problems for its inability to produce its promised U.S. supply of 25 million to 30 million flu vaccine doses. Chiron said it will be able to make 18 million to 26 million shots this year.

A spokesman for the Centers for Disease Control and Prevention in Atlanta said yesterday that it's possible U.S. health officials will have to prioritize during the coming flu season by providing flu shots first to high-risk populations such as the elderly and the seriously ill.

Last fall, the United States unexpectedly lost half its flu vaccine - about 48 million doses - after British officials closed Chiron's Liverpool, England, Fluviron plant because of contamination problems.

Chiron will undergo a Food and Drug Administration inspection of the Liverpool plant in July even though British officials have restored its license.

Chiron spokeswoman Alison Marquiss said yesterday that the Liverpool plant has "normal manufacturing issues" and it is simultaneously correcting conditions that caused it to lose the license last year.

Chiron chief executive Howard Pien held out only slim hope that the company might eventually make its target number of flu shots.

CDC spokesman Von Roebuck said the agency is monitoring the Chiron problem as well as flu vaccine production by other sources.

Roebuck said it's too early to assess the full impact of Chiron's problems. He said Sanofi-Pasteur is expected to provide 50 million shots to the United States and possibly 10 million more by late in the flu season.

And GlaxoSmithKline, which does not have a U.S. flu vaccine license but has applied for one, has said it could make 10 million initial doses and perhaps 5 million more. MedImmune is expected to supply 3 million doses of its nasal mist vaccine, Roebuck said.

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