Sanofi Shortens Shelf Life of Some H1N1 Vaccine Doses

For the third time in three months, Sanofi Pasteur and the CDC are notifying vaccine providers about potency issues with the manufacturer's novel influenza A (H1N1) vaccine in prefilled syringes.

In a Feb. 2 health update distributed through the CDC's Health Alert Network, agency officials said all lots of Sanofi's H1N1 vaccine in prefilled syringes that were not included in two earlier recalls -- one announced on Dec. 15 and the other on Jan. 29 -- should be administered by Feb. 15, regardless of the expiration dates printed on the products' packaging.

According to CDC officials, 50 vaccine lots were subject to the change in expiration date. The lots, which represent about 12 million doses, originally had expiration dates ranging from March 4, 2011, to June 11, 2011.

"The actual number of unused doses is likely much, much lower because most of those doses were shipped early in the season when things were being used immediately," said Anne Schuchat, M.D., director of the CDC's National Center for Immunization and Respiratory Diseases, during a Feb. 5 media briefing.

Prefilled syringes not used by Feb. 15 should be discarded in an appropriate manner or returned to Sanofi Pasteur Inc., the CDC said.

According to Schuchat, the FDA and vaccine manufacturers are looking into why some H1N1 vaccine lots have had potency issues.

In December, AstraZeneca's MedImmune biologics unit recalled 4.7 million doses of its live, attenuated intranasal H1N1 vaccine after nine lots failed stability testing.

Sanofi Pasteur's recalls covered nine lots of pediatric vaccine (0.25 mL) and one lot of vaccine for older children and adults (0.5 mL). More than 2 million doses were affected.

The CDC said there are no safety concerns with the vaccine, and people who received vaccine from the recalled lots or the lots with a shortened shelf life do not need to take any action. The agency also noted that the recalls and shortened expiration dates do not affect Sanofi Pasteur's H1N1 vaccine in multidose vials.

Schuchat said during the Feb. 5 media briefing that 124 million doses of H1N1 vaccine have been shipped, and about 70 million Americans have been immunized using 76 million doses (children under 10 are recommended to receive two doses). That works out to about 23 percent of Americans who have been vaccinated, she said, including 37 percent of children.