The Securities and Exchange Commission (SEC) started an informal inquiry after the suspension by the UK Medicines and Healthcare products Regulatory Agency (MHRA) of Chiron's license to manufacture Fluvirin influenza vaccine, which led to shortages last flu season.
In October 2004, Chiron was instructed to surrender to the US authorities documents and materials that would explain the events leading up to the suspension by the MHRA. At the time, the US justice department is said to be particularly interested in whether or not there was a delay in informing the authorities of any flaws in Chiron's manufacturing process.
Manufacturing and quality control deficiencies led to the vaccine becoming contaminated with a bacterium called Serratia. As a result Chiron could not export the 48 million flu vaccine doses, which accounted for nearly half the expected demand in the US.
Chiron said it is continuing to cooperate with the SEC's investigation, but would not comment further on why the probe had been upgraded to 'formal' status.
