The Food and Drug Administration (search) uncovered contamination and unsanitary conditions at a British flu vaccine manufacturing plant in 2003 but failed to re-inspect it until similar problems caused the loss of half the U.S. vaccine supply in October, the top FDA official said Wednesday.

FDA inspectors who visited the Chiron Corp. (search) plant in Liverpool in June 2003 found records of bacteria concentrations a thousand times the expected level, said a report distributed by Democrats at a hearing of the House Government Reform Committee.

The preliminary inspection report from last month indicates in three places that deficiencies found in 2003 had not been corrected.

But acting FDA Commissioner Lester Crawford (search) said the problems in 2003 and those that tainted this year's vaccine were unrelated. "The proof of that is that the 2003 vaccine production was completed on schedule and none of it was condemned," Crawford said.

Rep. Henry Waxman (search), D-Calif., said Crawford's assertion was part of a "pattern of misleading statements." The FDA might have averted or at least mitigated the vaccine shortage if it had been vigilant, Waxman said.

Instead, he said, the FDA rejected the recommendations of its inspectors for a formal warning to Chiron and asked the company to correct problems voluntarily.

Even after Chiron indicated on Aug. 25 that several million doses of vaccine had been contaminated, Waxman said, the agency remained passive, relying on weekly conference calls with the company rather than a new inspection.

"My criticism is that the FDA didn't do enough to stay on top of this," he said in one of several tense exchanges with Crawford.

British health authorities suspended Chiron's license on Oct. 5, citing manufacturing problems at the Liverpool plant. The company had been expected to ship roughly 50 million doses of its Fluvirin vaccine to the United States, about the half the nation's anticipated supply.

So far, federal officials have found a few million additional doses from Aventis Pasteur, the other manufacturer of an injectable vaccine, and MedImmune, which makes a mist that can be inhaled.

The Bush administration is seeking to acquire another 5 million doses from Canada and Europe. State and local governments have identified 750,000 more doses they can buy from wholesalers, but need FDA approval.

Crawford, backed by committee Republicans, strongly defended his agency's actions in inspecting and monitoring conditions at the Chiron plant.

There was no need for FDA inspectors to return to Liverpool after the June 2003 visit because the company "did what we wanted them to do," producing a sterile supply of flu vaccine, he said.

Bacteria is endemic to flu vaccine production because the process begins with chicken eggs, Crawford said. The production process is designed to render the vaccine sterile, and there is no tie between one year's batch and the next's, he said.

Republicans said there was an FDA team at the Chiron facility on Aug. 25 for unrelated reasons. When the first word of contamination surfaced, FDA employees looked at the vaccine production line and alerted U.S. authorities, they said.

They noted that the FDA followed its standard procedures and called Waxman's charges "another partisan attack on the administration."

For his part, Waxman said the FDA's statements prior to the Nov. 2 election were designed to reassure people "about the flu vaccine shortage and the administration's reaction."

Waxman acknowledged in his report that FDA officials said Chiron's decision to increase production by a third, from 38 million doses last year, played a significant role in the magnitude of the contamination at the Liverpool plant.