by bintangkecil on Tuesday, December 15th, 2009 | Health, News

Almost 800,000 children’s doses of H1N1 swine flu vaccine have lower strength than needed for protection. These vaccines have been recalled by a pharmaceutical company Sanofi Pasteur Inc. because they have lost some potency, federal health officials said Tuesday.

According to the U.S. Centers for Disease Control and Prevention, the company’s routine testing of the vaccine for children aged 6 months to almost 3 years found that four batches had lower than required potency levels. “This means that doses from these four vaccine lots no longer meet the manufacturer’s specifications for potency,” according to the CDC.

Potency (or strength) is determined by the measurement of the concentration of the active ingredient (also called antigen) in the H1N1 vaccine.

“This is not a safety problem; it’s an issue of efficacy,” said infectious disease expert Dr. Marc Siegel, an associate professor of medicine at New York University, in New York City.

Siegel said this recall is good news because it means the vaccine is being tested after it is shipped. “I am happy to see them testing this, because one of the things that happens is once a vaccine gets to market it kind of gets forgotten,” he said.

Specifically, the recalled doses are in single shot pre-filled syringes, and do not contain the preservative thimerosal. To be protected from swine flu, children under 10 need two shots spaced about a month apart.

“I don’t think this is a coincidence that this is occurring in the single-dose syringes,” Siegel said. “This process is very labor-intensive. The more intensive the process, the more likely we will see variation in efficacy.”

Although the manufacturer is asking that unused doses be returned, the vaccine itself is safe. “There are no safety concerns with these lots of H1N1 vaccine. All lots successfully passed pre-release testing for purity, potency and safety,” the CDC said.

FAQs on the recall of certain lots of Sanofi Pasteur H1N1 Pediatric (0.25 mL, for 6-35 month olds) Vaccine in Pre-Filled Syringes from the CDC website:

Are there any concerns about safety of vaccines from these lots?
No. There are no safety concerns with these lots of H1N1 vaccine. All lots successfully passed pre-release testing for purity, potency and safety.

Should infants and children who received vaccines from these lots be revaccinated?
No. The vaccine potency is only slightly below the “specified” range. The vaccine in these lots is still expected to be effective in stimulating a protective response despite this slight reduction in the concentration of antigen. There is no need to re-administer a dose to those who received vaccine from these lots. However, as is recommended for all 2009 H1N1 vaccines, all children less than 10 years old should get the recommended two doses of H1N1 vaccine approximately a month apart for the optimal immune response. Therefore, children less than 10 years old who have only received one dose of vaccine thus far should still receive a second dose of 2009 H1N1 vaccine.

What action(s) should parents of children who have received vaccine from the recalled lots take?
Parents of children who received vaccine from the recalled lots do not need to take any action, other than to complete the two-dose immunization series if not already completed.

What are the lot numbers affected by this recall?
Vaccine doses with the following lot numbers are included in the recall:

0.25 ml pre-filled syringes, 10-packs (NDC # 49281-650-25, sometimes coded as 49281-0650-25):
UT023DA
UT028DA
UT028CB

0.25 ml pre-filled syringes, 25-packs (NDC # 49281-650-70, sometimes coded as 49281-0650-70):
UT030CA

What is being done to notify providers who received vaccine from the affected lots?
Sanofi Pasteur will send a notification to providers who received doses from any of the four lots of vaccine so that they can return any unused vaccine.

Where were the affected lots of vaccine distributed?
Vaccine from these four lots was distributed throughout the United States.

Tags: cdc, Dr. Marc Siegel, h1n1 recall, h1n1 vaccine recall, Phillies, sanofi pasteur, swine flu recall, swine flu vaccine recall, swine flu vaccines recall