Reduced potency prompts another H1N1 vaccine recall

Feb 2, 2010 (CIDRAP News) – The Centers for Disease Control and Prevention has notified state and local health departments of a recall of pre-filled syringes of H1N1 flu vaccine made by Sanofi Pasteur Inc because of a decrease in potency.

It is the second voluntary, non–safety-related recall of H1N1 vaccine made by Sanofi, which recalled pre-filled syringes of pediatric vaccine in mid-December for the same reason.

The current recall involves five lots of single-dose pediatric flu vaccine and one lot of single-dose vaccine for older children and adults. All the lots were shipped between November 2009 and January 2010, the CDC said.

Len Lavenda, vice president of U.S. communications for Sanofi, told CIDRAP News that the vaccine lots totaled about 1.3 million doses, which were distributed nationwide. "We don't how many remain unused," he said.

The CDC said the recall was triggered when quality-assurance testing showed that the potency of the vaccine lots had dropped below the manufacturer’s pre-specified threshold. The lots met Sanofi’s thresholds for potency, and for safety and purity, at the time of release, the agency said.

Vaccines in the affected lots are expected to still produce an immune response if used, the CDC said, and there is no need to re-immunize anyone who was given a dose from one of the lots.

Lavenda told the Pocono Record newspaper that the company cannot currently explain the vaccine’s drop in potency after shipment. "We don't know the reason for this. We are launching a very thorough investigation," he said.

Sanofi is not the only company that has recalled H1N1 vaccine in the United States. MedImmune, maker of the nasal spray H1N1 vaccine, recalled leftover doses from 13 lots of vaccine in December, also because of a slight loss of potency (antigen content).

See also:

Jan 29 Health Alert Network notice

Feb 2 Pocono Record article

Dec 15, 2009, CIDRAP News story "Sanofi recalls some pediatric pandemic vaccine doses"

Dec 22, 2009, CIDRAP News story "Slight loss of potency prompts recall of nasal H1N1 vaccine"

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