AstraZeneca's MedImmune unit is recalling 4.7 million doses of their nasal spray vaccine voluntarily due to potency concerns. While the slightly lower potency levels noticed during follow-up by the company led them to recall the vaccines, there is no reason for patients who have already been vaccinated to be revaccinated, according to the FDA.
MedImmune is the second H1N1 vaccine distributor over the past month to recall some of their vaccines because of problems with the potency. Around 800,000 doses of pediatric H1N1 injectable vaccine doses produced by Sanofi-Aventis were recalled on December 15 when the company discovered the potency was not high enough. In the case of the MedImmune’s recall, the recall was not for safety concerns, but as a precaution in case some of the affected dosages were being stored. MedImmune’s recall recommends all lots expiring between January 19 and January 26, 2010 be discarded and not administered. The affected lots were distributed in October and November of 2009, when the potency was still full force, according to Norman Baylor with the FDA.