About 800,000 doses of swine flu vaccine, made by Sanofi Pasteur SA, have been recalled after testing indicated they may not be potent enough to protect against the virus, according to the U.S. Centers for Disease Control and Prevention (CDC).
The recalled shots are preservative-free syringes of a low- dose version made for children ages 6 months through 25 months, said Anne Schuchat, head of the National Center for Immunization and Respiratory Diseases at the CDC.
At this time, health officials are unsure how many doses have already been given. However, there is no safety concern and children vaccinated from the lots already will not need to be re-vaccinated, CDC said.
While the lots initially passed potency testing when they were first shipped, later tests appear to indicate the potency waned. The company has notified the FDA.
According to CDC estimates, swine flu has killed 10,000 Americans since it emerged in March and put 200,000 into the hospital.