Autism and vaccines: Is there a link?
(CNN) -- A congressional committee is holding hearings Tuesday into the relationship between childhood vaccinations and autism. According to the House Government Reform Committee, as many as 1.5 million Americans suffer some form of autism, and the rate is increasing by 10 percent to 17 percent a year. Many people believe thimerosol, a mercury-based preservative used in some vaccines, may be partly to blame for these statistics, but many scientists dispute that theory.
Rep. Dan Burton, R-Indiana, who chairs the committee, also has a personal stake in the inquiry: He's the grandfather of a 5-year-old who was diagnosed with autism three years ago. Burton joined CNN's Leon Harris and childhood immunization expert Dr. Sharon Humiston, also the mother of an autistic child, to discuss the issue.
HARRIS: Good to see you again, Congressman. How is your grandson doing?
REP. BURTON: He's doing a little bit better. He still has severe speech problems. But he's doing a little better.
HARRIS: Well, that's good to hear. Here's hoping it gets even better down the road. So what is it you hope to accomplish with these hearings this afternoon?
BURTON: Well, first of all, I think that the public needs to know about some of the problems that we have with vaccines. I'm a strong advocate for vaccines. I think they're important for the health of the nation.
But at the same time, some of the vaccines, I think, have not been tested as well as they should have been. Some of the contents in the vaccines should not be in there, like thimerosol, which contains mercury, and mercury has a cumulative effect on the brain, and causes -- I believe it's a contributing factor to autism. So these [are] things I think that should be looked into by the Food and Drug Administration and Health and Human Services, and I don't believe they've done as good a job as they should have.
HARRIS: There's some, and doctors even, who have come up with distinctly different opinions about that, saying that the science behind all that isn't that strong.
BURTON: Well, we have had scientists from all over the world come in and testify, scientists from the United States. There is no question that mercury is a toxic substance that affects people and causes neurological damage. They've taken it out of topical dressings in 1985, and yet they continue to put it into our children and adults, in flu vaccines, and there's a growing body of evidence that it may be a part of the Alzheimer's problem we have.
So mercury, which is a toxic substance, should not be injected into human bodies in any way that's avoidable.
HARRIS: We've heard that said about mercury quite a bit over the years. Pediatrician Sharon Humiston has a different perspective. She is an expert on childhood immunization, and she's the author of "Vaccinating Your Child: Questions and Answers for Concerned Parents." She's also the mother of a 9-year-old autistic son.
Doctor Humiston joins us now from Rochester, New York, where she is on the faculty of the University of Rochester Medical School.
Thank you for taking time with us this morning.
How is your child doing?
DR. HUMISTON: My son at 9 still doesn't have language, but he's a wonderful boy.
HARRIS: We're glad to hear that. And again, as well with you, we hope that this gets better down the road.
Now, can you respond to these statements that we've just heard from Congressman Burton about the signs being so clear that these vaccines have some sort of a link to autism. What do you think about that?
HUMISTON: I think quite the opposite. The overwhelming evidence is that vaccines don't cause autism.
Most recently a study from Denmark showed in hundreds of thousands of children that there was no link between autism and MMR [the measles-mumps-rubella vaccine]. What I'm concerned about is that hammering away at this theory is going to do two things: take away resources from furthering the science of autism and second, plant the fear in the hearts of parents so that we're going to see a decrease in immunization rates and an increase in disease.
BURTON: May I comment on that? Yes, in 1992, they took thimerosol out of vaccines in Denmark, and that is a flawed study, number one. And I would like to ask the doctor if she categorically says that there is no doubt whatsoever that mercury in vaccine causes -- is a contributing factor of autism. No doubt whatsoever in her mind, not at all?
HUMISTON: We know that thimerosol has been out of vaccines for years in the United States, and there's no appreciable decrease in autism.
BURTON: That is not the question.
HUMISTON: So we have strong evidence, even from the United States, that thimerosol doesn't cause autism. There is a confusion here, too, between MMR and thimerosol. MMR has not now and never had thimerosol in it. The parents shouldn't be confused about those two issues.
BURTON: Well, there is a concern. ... What I asked you is, can you categorically say without any doubt whatsoever that the mercury in vaccine does not contribute to neurological problems?
HUMISTON: Of course I'm a scientist. And scientists...
BURTON: That is not an answer. You will not answer, will you?
HUMISTON: Scientists can't say things in a way that a politician can say them, because scientists can only prove things that are so. We can build evidence. So that's what I'm saying is, that for my child, science will help him more than emotion.
BURTON: Let me say this about emotion... about science. We have had scientists from all over the world, including here in the United States, that say that the mercury in vaccine really causes neurological problems. We have had a scientist in Canada sent us a video showing that a very minute amount of mercury in the brain destroys the sleeve that controls the nerve in the brain.
So there's no question that mercury in our bodies does cause neurological problems. And for the doctor to evade the question about knowing for sure that mercury doesn't cause neurological problems in these vaccines shows very clearly that she simply doesn't know. She's an educated lady, no question about it, but she's not going to give you a straightforward answer.
HARRIS: All right, we'll have to leave it there. We can see why this is such an interesting and controversial topic.