Vaccine potency plunge problematic

What accounts for the low antigen level of the Sanofi-Aventis H1N1 vaccine for kids?

The recalled 800,000 doses, in 0.25-mL pre-filled syringes intended for 6- to 35-month olds, have been found to be safe. They're apparently just a little less robust than they ought to be. So says the CDC, which along with the FDA was informed of the spec deviation by the manufacturer after routine QA testing. The four lots passed pre-release testing for purity, potency and safety. So what happened?

Little information is available from the customary public sources on what might have happened. In fact, for the recall of such a high-visibility product--one that includes both "pandemic flu" and "infants" in its description--there is scant information to be found anywhere.

The CDC site leads in information available. It says that Sanofi is investigating, and that the same vaccine packaged in other dosing forms, such as pre-filled syringes for older children and adults, and multi-dose vials, continue to meet specs.

Whatever the problem is, Sanofi appears confident in its ability to make a fix: The company announced just two days after the recall that it aims to double its vaccine sales by 2013, according to Reuters. And that H1N1 vaccines would boost fourth-quarter sales by $500 million and maintain that pace into 2010.

- see the CDC info
- here's the Reuters report