On Sept. 28, 2007, the U.S. Food and Drug Administration (FDA) approved an Australian-made influenza vaccine called Afluria for use in adults, raising the number of U.S.-licensed flu vaccines to six.

The vaccine, made by CSL Limited, based in Parkville, Australia, was approved for protecting people aged 18 and older from type A and B influenza viruses.

Like most flu vaccines, Afluria contains inactivated (killed) flu viruses grown in chicken eggs. People who are allergic to eggs should not receive the vaccine, the FDA said in a news release.

The vaccine is given as a single injection in the upper arm. It will be available in single dose, preservative-free syringes and in multiple-dose vials containing thimerosal, a mercury compound, as a preservative, the FDA said.

CSL expects to supply up to 2 million doses of the vaccine in the United States this season, according to Paul Perreault, executive vice president of commercial operations for the company’s US division, CSL Biotherapies, based in King of Prussia, Pa. Plans call for delivering all the doses to the United States by the end of October, the company said in a news release today.

The FDA said the Centers for Disease Control and Prevention (CDC) has estimated that the six vaccine makers will supply a record total of 132 million doses of flu vaccine in the United States this year. The CDC had cited the same figure at a news conference last week, without mentioning the CSL vaccine.

CSL Biotherapies announced its filing for FDA approval of Afluria in April. The application included the results of a phase 3, randomized, placebo-controlled clinical trial that involved 1,357 volunteers at nine US sites, the company news release said. Sponsored by the National Institutes of Health, the study evaluated the safety and immunogenicity of thimerosal-free and thimerosal-containing formulations of the vaccine.

The FDA used its accelerated approval pathway in evaluating the vaccine. “The manufacturer demonstrated that the vaccine induced levels of antibodies in the blood likely to be effective in preventing seasonal influenza,” the agency said. “As part of the accelerated approval process, the manufacturer will conduct further studies to verify that the vaccine decreases seasonal influenza disease after vaccination.”

CSL-branded flu vaccines are approved and sold in 16 countries, and the company provides bulk antigen for flu vaccines sold in 24 countries, according to the CSL news release. Officials said the company has been making flu vaccines for 40 years.