Children's H1N1 Swine Flu Vaccine Recalled


Sanofi Pasteur has issued a voluntary recall of unused 800,000 H1N1 swine flu vaccines because their potency has diminished since manufacture.

The H1N1 swine flu vaccines were packaged as pre-filled syringes and intended for children between the ages of 6 and 35 months. They were shipped in mid to late November and early December. The vaccines met specifications at the time of shipment, however the antigen content was detected by the manufacturer to be “only slightly below” the specification limit. The reason for the drop in potency is unclear at this time.

“While the antigen content of these lots is now below the specification limit for the product, CDC and FDA are in agreement that the small decrease in antigen content is unlikely to result in a clinically significant reduction in immune response among persons who have received the vaccine. For this reason, there is no need to revaccinate persons who have received vaccine from these lots,” the notice reads.


John Treanor, MD, of the University of Rochester in New York, said that "a 10% drop in potency would mean, effectively, instead of getting a dose of 15 micrograms a person would be getting a dose of 13.5 micrograms. In studies that we and others have done with seasonal vaccine in adults, there is no substantial difference in the immune response between a dose of 15 micrograms and one of 7.5 micrograms, so I can't imagine that the effect of a 10% decrease in potency of this vaccine would be even noticeable," he said.

The recalled H1N1 swine flu vaccine doses come from four lots of 0.25-mL pre-filled syringes for pediatric use in both 10-packs (lot numbers UT023DA, UT028DA, and UT028CB) and 25-packs (lot number UT030CA). The H1N1 swine flu vaccine recall does not affect any of the vaccine for adults or products from other manufacturers.

Because of the high demand for the vaccine, the vaccines were most likely used before their potency dropped below recommended levels. Children under the age of 10 are recommended to have two vaccinations for H1N1 spaced about one month apart, as their immune systems are not fully developed.

Dr. Anne Schuchat, a CDC flu expert, stressed that parents don't need to do anything or to worry. The vaccine is still safe,” she said.

The vaccine for H1N1 has been available since early October, and health officials estimate that 95 million doses have been distributed in the United States.