WASHINGTON-- None of the flu vaccine quarantined in Britain last week is safe for Americans to use, US health officials confirmed yesterday, ending last hopes that at least some of the shots would prove salvageable.
More testing uncovered additional contaminated batches of
''We believe all of the lots produced by that plant are suspect at this point," said Lester Crawford, acting commissioner for the Food and Drug Administration. ''So we cannot allow them to be used."
Crawford's comments came as FDA scientists finished a weeklong stint at the Liverpool, England, factory where Chiron had made about 48 million doses of flu vaccine originally destined for US use.
Britain last week unexpectedly shut down that plant, cutting the US supply of flu shots in half. The nation's sole remaining supplier, Aventis Pasteur, has produced 55.4 million doses. Roughly 20 million of them have yet to be shipped.
The government is urging healthy adults to skip the shot this year so those remaining doses can go to the youngest, oldest, and sickest Americans, who are most vulnerable to influenza.
Chiron had alerted the FDA in August that a few batches of its vaccine were contaminated with a worrisome bacteria called serratia. But US officials were convinced by further company testing that the rest of the shots probably would be fine.
Instead, additional batches have been found to be contaminated. Crawford didn't give a precise number.
Crawford said yesterday that it appears the contamination occurred in a final step of vaccine production, when the bulk product is put into individual vials. That step requires final sterility testing, and Chiron was scheduled to give FDA an update Oct. 5, the same day British regulators cracked down.
Asked whether FDA would have uncovered the problem had its British counterparts not acted, ''definitely," Crawford replied. ''We would have found it basically on the same day the British announced their conclusions."
Chiron has in a US warehouse more than 1 million doses of the vaccine shipped before last week. FDA will examine those doses more closely to see whether they might be usable, but it's highly unlikely, Crawford said.