Clinical trials for the H1N1 swine flu vaccine have now reached the two-month mark. Researchers say the results are promising so far.
At Baylor University, there is one ingredient missing from the pediatric version of the vaccine they are testing: Thimerosal. It's a mercury-based preservative whose safety has been debated for years. It's a debate that has Sarah Harm unwilling to give her daughter any vaccines.
"No chemicals, no preservatives, nothing of that nature," she said.
A growing chorus of parents, and some medical professionals, believe that Thimerosal is linked to autism. The internet is home to thousands of those claims, but researchers say they are groundless.
"No it's not a concern anyway because there's been no evidence that it produces any harm," said Dr. Paul Glezen, Baylor College of Medicine.
Thimerosal is present the majority of seasonal flu vaccine shots, except for some pediatric versions. And it will be in some, but not all types of the swine flu vaccine.
Here's the rundown:
- The vaccine multi-dose vials will contain Thimerosal to prevent contamination between doses.
- Single-dose vials coming out later will not contain it.
- Neither will any of nasal-spray vaccines which are recommended for healthy people, ages 2-49, but not for pregnant women.
Dr. Glezen says if you're concerned, you should request Thimerosal-free vaccine.
"Because it is available," he said.
Of course, high risk groups will be still get priority. That list includes pregnant women; the young, ages 6 months through 24 years; people younger than 64 who have conditions such as asthma or diabetes that increase the risk of complications from flu; health workers and caregivers of newborns.
The CDC says that the Thimerosal version is safe for pregnant women who should also get the seasonal flu shot.