Earlier this week, the Food and Drug Administration approved the long awaited vaccine for H1N1 swine flu. The government has ordered 195 million doses of it, with the first supplies expected to arrive in early October. It's recommended that the elderly, pregnant women and children get the shot because they have higher death rates from swine flu. But some parents may be hesitant to vaccinate their children due to fears of a rare but very serious side effect.
One of the ingredients in the vaccine is thimerosal, which is a preservative commonly used in vaccines. But thimerosal is a form of mercury, which can be toxic, especially for pregnant women and young children, Baylor College of Medicine vaccine expert Carol Baker told USA Today. But Baker, a member of the government’s Advisory Committee on Immunization Practices, was quick to point out in a Q & A with the paper:
...thimerosal, made of ethyl mercury, is different from the methyl mercury found in fish. Methyl mercury can cause congenital problems in fetuses. The ethyl mercury used in vaccine isn’t thought to pose a problem, especially because it’s used in trace amounts.
Indeed, most studies have found that thimerosal is harmless. "We have yet to find any evidence that thimerosal ever hurt anyone," said Dr. Andrew Pavia, chief of Pediatric Infectious Diseases at the University of Utah told ABC News.
But there is still serious concern. This fear mostly stems from the the 1976-77 flu season when a vaccine developed to prevent the spread of a strain of the swine flu was linked to a still-unexplained increase in cases of a rare neurological condition known as Guillain-Barre syndrome in those who received immunizations.
Many groups opposed to current vaccination practices continue to condemn thimerosal as a toxin responsible for the development of autism and related ailments in children. "We don't have adequate safety studies on this vaccine before we are moving forward to market," said Lyn Redwood, president and co-founder of the group SafeMinds. "I'm really not convinced that we know for sure that the risk of the disease outweighs the risk of the vaccine, especially since this is a brand new additive that we have never used before in combination with thimerosal."
But medical experts say the fear is unfounded, pointing out that that is the reason why we have the FDA.
"I see no reason to anticipate major safety concerns with this vaccine," said Dr. Peter Hotez, a professor and chair of the Department of Microbiology, Immunology and Tropical Medicine at George Washington University. "The vaccine will be tested and licensed, and the FDA will not allow it to go forward unless the vaccine is shown to be safe and elicit an effective immune response."
The maker of the vaccine, Sanofi-Aventis, insists it is safe. Even still, spokeswoman Donna Cary says the company is anticipating making two versions -- one with thimerosal, and one without. So parents who still have concerns about thimerosal should have an option.