Some swine flu vaccine for children recalled for potency drop

By Elizabeth Cooney, Globe Correspondent

Just when swine flu vaccine seemed to be flowing smoothly after earlier production delays, 800,000 doses meant for young children are being recalled because their potency has waned, health officials said today. But the drop in strength was so slight that revaccination will not be necessary if the shots were already given, they advised.

Pre-filled syringes of vaccine intended for children between 6 and 35 months old -- including some doses shipped to Massachusetts doctors -- are being recalled because their strength fell between the time the vaccine was manufactured and when it was distributed, according to an advisory sent today from the US Centers for Disease Control and Prevention. Four lots from manufacturer Sanofi Pasteur no longer meet the specified range for potency, the company said based on routine testing. Safety is not involved in the recall.

The CDC, which tracks how vaccine is allocated to health-care providers, is notifying individual doctors and asking them to return any doses from lots that have been recalled. At least one of those lots contained vaccine sent to doctors in Massachusetts, said Jennifer Manley, a spokeswoman for the state Department of Public Health.

"We don't know how many yet," she said. "We do know there is some in the state. We are hoping to get a list from CDC but we don't think it will be today."

Parents whose children have already been vaccinated don't need to do anything, even if it turns out the vaccine came from one of the recalled lots, state and federal health officials said. Children under 10 years old need to get two doses of vaccine about a month apart for full immunization against the H1N1 virus.

The recall affects only single-dose syringes, CDC said. Multidose vials have not had a potency drop. Vaccine given as a nasal spray is also not affected by the recall.

Since swine flu virus first emerged in the spring, vaccine manufacturers have struggled to produce vaccine for both swine and seasonal flu. It took longer than anticipated for vaccine to arrive, and when it did, health officials initially restricted doses for high-risk groups. Children and pregnant women were at the top of the list because swine flu has stricken those two groups harder than others.