(Adds details from FDA, company comments, byline)
CHICAGO, Dec 22 (Reuters) - The U.S. Food and Drug Administration said on Tuesday AstraZeneca's AZN.L MedImmune unit is voluntarily recalling some of its H1N1 swine flu vaccine because it was not as potent as it should be.
Norman Baylor, director of the office of vaccines research and review at the FDA, said the recall involves a total of 4.7 million doses of the company’s nasal spray vaccine, but only about 3,000 of those doses are left in warehouses.
The rest of the doses were given out in October and November, when the vaccine was still at full potency, Baylor told reporters on a conference call.
The FDA said people who had already received the vaccine do not need another dose.
The company is the second to recall H1N1 swine flu vaccine in the past month. Sanofi-Aventis SA SASY.PASNY.N on Dec. 15 recalled 800,000 doses of its pediatric H1N1 swine flu vaccine because it is not as potent as it should be.
MedImmune said in a statement the recall involves unused doses of 13 specific lots of 2009 H1N1 nasal spray vaccine, because of a slight decrease in potency that was detected during regular checks.
“The doses were well within potency specifications at the time of distribution,” said Tor Constantino, a spokesman for the unit of AstraZeneca.
He said the recall was not for safety issues, but was intended to notify any healthcare providers who may still have some of the recalled vaccine in their refrigerators.
“The cause of the loss of potency is being investigated,” Constantino said by telephone, adding that this has not been an issue in the past with the company’s seasonal flu vaccine.
MedImmune is recommending that all lots marked with an expiration date of between Jan. 19 and Jan. 26, 2010 not be used.
Constantino said the company has delivered 23 million of the total 40 million doses on its contract with the U.S. government. He said the recalled doses were some of the earliest the company made, and most have already been given to people.
The U.S. Health and Human Services Department has contracts with five companies to make 251 million doses of H1N1 vaccine as well as seasonal flu vaccine -- Sanofi Aventis SASY.PA, CSL of Australia CSL.AX, AstraZeneca AZN.NAZN.L unit MedImmune and GlaxoSmithKline GSK.L.
The CDC’s Dr. Anne Schuchat said on Tuesday 111 million doses of H1N1 vaccine have been made available so far.
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