Vaccine manufacturer Sanofi-Aventis is recalling 800,000 doses of vaccine against the pandemic H1N1 virus meant for children younger than 3 because the vaccine has lost potency since it was shipped from the factory.
"This is non-safety related, but is part of a routine quality assurance program," Dr. Anne Schuchat, director of the Centers for Disease Control and Prevention's National Center for Immunization and Respiratory Diseases, said in a telephone interview. There are now 94.6 million doses of vaccine available, "so this is not as big a deal as it might have been earlier." She emphasized that "there are no safety concerns."
The doses in the recall are pre-filled syringes containing thimerosal-free vaccine made specifically for children ages 6 to 35 months old. At the time of manufacture, testing showed that the doses contained the recommended 7.5 micrograms of antigen, the virus component that is used to stimulate immunity. But later testing showed that some of the antigen had apparently degraded, leaving the vaccine less potent than desired. It is not yet known why that happened, Schuchat said, but it doesn't appear to be a storage issue.
Children who received the vaccine do not need to be re-immunized, she added, because they probably received a sufficient dose, "but we wanted to make sure that doses that weren't already given won't be," she said. She emphasized that children who have only received one dose of the swine flu vaccine should get their scheduled second dose. Two doses are required to provoke full immunity in children younger than 10, just as is the case with seasonal flu vaccine.
-- Thomas H. Maugh II