Aug 31, 2005 (CIDRAP News) – Prospects for an adequate supply of seasonal influenza vaccine this year brightened today with federal approval of a new flu vaccine and a report of progress in fixing problems at Chiron's flu vaccine plant in England.
The Food and Drug Administration (FDA) today announced approval of GlaxoSmithKline's (GSK's) Fluarix vaccine for use in adults. In addition, the FDA said Chiron has made "significant progress" in addressing problems at its flu vaccine plant, where contamination last year forced the company to scrub the sale of about 48 million doses of vaccine to the United States.
Referring to both developments, Curtis Allen, a spokesman for the Centers for Disease Control and Prevention (CDC), told CIDRAP News, "This is very good news. We're cautiously optimistic, but there are still things that are unknown."
Allen, who works in the CDC's National Immunization Program, said the CDC currently estimates the US flu vaccine supply for this season will range from about 79 million to 87 million doses. That includes 50 million doses from Sanofi Pasteur, 3 million doses from MedImmune, 8 million from GSK, and between 18 million and 26 million from Chiron.
"That would be roughly equivalent to the number of doses that are used in a typical flu season," Allen said.
The demand for flu shots this year, in the wake of last year's shortage, is a big unknown, he said. "We don't really know how the public is going to react this year and the impact of last season on [vaccine] uptake." People who didn't get vaccinated during last year's shortage and never caught the flu may feel they don't need a shot, while others may hurry to get a shot because they fear another shortage, Allen said.
He said some recommendations on priorities for flu immunization would be published tomorrow in the CDC's Morbidity and Mortality Weekly Report.
The FDA said Fluarix, which contains inactivated flu virus, is the first vaccine to gain approval under the agency's accelerated approval process. The process allows the FDA to license products on the basis of results that are "reasonably likely to predict ultimate clinical benefit," as opposed to actual proof of efficacy.
"Accelerated approval has allowed us to evaluate and approve Fluarix in record time so that we can make available additional safe and effective flu vaccines," FDA Commissioner Lester Crawford said in a news release. "I commend our Center for Biologics for taking extraordinary steps to help us be better prepared for both the upcoming and future flu seasons."
GSK showed that Fluarix generated levels of protective antibodies that are likely to be effective in preventing flu, the FDA said. The agency said it evaluated data from four clinical studies involving about 1,200 adults, as well as data from post-marketing reports from other countries where the vaccine is used. Officials said they would also require the company to conduct further clinical studies.
Fluarix has been in use since 1992 and is currently distributed in 92 countries, GSK said.
The report on progress at Chiron's British plant came after a 9-day FDA inspection in July and subsequent communications between Chiron and the FDA. The company said in a news release, "The FDA found Chiron's responses and proposed corrective actions to the FDA inspection observations . . . to be 'generally acceptable.'"
Dr. Jesse Goodman of the FDA said in a statement, "The letter that we issued to them this week is a positive development and shows significant progress on their part. However, additional work is needed to determine the amount of vaccine Chiron may be able to supply the U.S. market for the upcoming flu season. FDA will evaluate the implementation and effectiveness of their corrective actions going forward. In addition, any vaccine produced must pass all tests for safety and potency before it can be marketed in the U.S."
The British government suspended Chiron's manufacturing license when contamination was found at the plant last year. But British regulators authorized the company to resume production in March, after the company improved its equipment and processes.
"We remain focused on our objective of delivering Fluvirin vaccine to the US market in support of public health efforts to prepare for the upcoming influenza season," Chiron CEO Howard Pien said in the news release.
FDA announcement of Fluarix approval