British health authorities Wednesday cleared the way for Chiron Corp. to resume flu vaccine production immediately, ending a five-month suspension that created temporary shortages in the U.S. last fall.
Although the factory in Liverpool still faces regulatory hurdles, analysts on Wall Street said they expected Chiron would provide shots to the United States later this year, easing worries about another season of scarcity.
The timing of the British action was important. Because it takes four to five months to produce millions of doses of vaccine from chicken eggs, Chiron needs to begin manufacturing its shots by early spring in order to reach the market by fall.
"All issues that have caused the concerns have been satisfied," said Vicky Wyatt, a spokeswoman for the Medicines and Healthcare Products Regulatory Agency, the British counterpart to the U.S. Food and Drug Administration.
"We are happy to have them resume manufacturing of the vaccine."
Chiron said it started producing vaccine as soon as the suspension ended in Britain. The Emeryville, Calif., company said it looked forward to returning to the flu shot business in a "meaningful way."
Flu vaccine is Chiron's biggest product, and last year's fiasco cost the company $300 million in revenue.
"This is a significant accomplishment," Chief Executive Howard Pien said in a statement.
Pien said the company remained focused on resolving all outstanding problems at the Liverpool plant. Chiron must provide weekly progress reports to British regulators, and the FDA must sign off on plant improvements.
Jesse Goodman, director of the FDA division that oversees vaccine companies, said in a statement that the restoration of Chiron's license in Liverpool "was an extremely important milestone in Chiron's efforts to supply influenza vaccine for the U.S. market."
Goodman said that "work remains" and that the FDA and its British counterpart would continue to monitor Chiron. The FDA will conduct an inspection after "all critical stages of manufacturing are in full swing and needed corrective actions can be fully evaluated," he said.
Neither Chiron, the FDA nor British authorities provided details on what remedial tasks still remain for Chiron.
In October, British regulators stopped Chiron from shipping 48 million doses of Fluvirin vaccine to the United States because of sloppy manufacturing practices and evidence of bacterial contamination in the Liverpool factory.
