CDC recalls hundreds of thousands of H1N1 vaccine shots

The Center for Disease Control has issued a voluntary recall of hundreds of thousands of pediatric H1N1 swine flu shots for “non-safety” reasons.

Those who have been vaccinated need not receive a second shot, the CDC said.

The vaccines, given to children aged six to 35 months of age, have been recalled because tests have indicated that the though they are still safe, the doses have lost some of the original strength, WebMD Health News reports.

On December 7, the CDC and FDA were notified by vaccine creator Sanofi Pasteur that one lot of the syringes had dropped below the pre-specified active ingredient limit.

“As a result of this finding, Sanofi Pasteur tested additional lots and found that three other lots that had been distributed also had an antigen content that, while properly filled at the time of manufacturing, was later measured to be below pre-specified limits,” the CDC report said, according to WebMD Health News. “This means that does from these four vaccine lots no longer meet the manufacturer’s specifications for potency.”

Children and infants who received these vaccines do not require revaccination because the potency was only slightly below the effective range and it should still be effective.

“Sanofi Pasteur is investigating what caused the problem,” the CDC said, according to WedMD Health News. “The same vaccine packaged in other dosing forms, such as pre-filled syringes for older children [and] adults and multidose vials, continues to meet specifications.”