December 23, 2009
MedImmune is conducting a non-safety-related voluntary recall of 13 lots of monovalent 2009 (H1N1) nasal spray vaccine, representing 4.7 million doses. Routine testing found the potency had fallen below a pre-specified limit or was at risk of falling below that limit in the next week. This slight decrease in vaccine potency is not expected to have an impact on the protective response to vaccination. Therefore, there is no need to recall patients who received doses of vaccine from the recalled lots, and extra doses of vaccine are not required. There are no safety concerns with these lots of 2009 H1N1 vaccine. All lots successfully passed prerelease testing for purity, potency and safety. However, because their potency is now or might soon be below the specified lower limit, MedImmune will send providers directions for returning any unused vaccine from these lots.

Since most lots were shipped in October and early November, it is likely most of the vaccine was used while it was still within specified potency. The CDC has prepared a fact sheet on this recall.

The affected lot numbers are:

500751P
500754P
500756P
500757P
500758P
500759P
500760P
500761P
500762P
500763P
500764P
500765P
500776P

Additional information is available from MedImmune:
http://www.medimmune.com/pdf/H1N1_Recall_QandA_122209.pdf
http://www.medimmune.com/pdf/H1N1_Recall_letter_122209.pdf