We are responding to the column "Are Vaccines, Mercury and Autism Linked?" in the Health & Wellness section of the May 16 Jewish Times.
As pediatricians we often speak with parents who have concerns about the safety of vaccines. Unfortunately, their fears are usually based on incomplete, nonscientific information such as Lewis Regenstein presented.
Routine childhood vaccination has produced a tremendous decline in serious infections the past 100 years. Innumerable lives have been saved and suffering prevented.
Before vaccination, nearly everyone developed measles as a child. Each year in the United States, about 50,000 were hospitalized, and there were 1,000 cases of permanent brain damage and 500 deaths. There are now fewer than 100 cases yearly and no deaths.
Polio paralyzed 20,000 people per year, causing 1,000 deaths. Polio has now been eliminated from the Western Hemisphere.
Vaccines do a wonderful job of preventing illness and long-term complications and of saving lives.
Vaccines are safe. Prior to being made available to all children, vaccines are extensively studied to demonstrate that they provide protection. This research includes testing new vaccines with existing vaccines that would be given at the same time. The new vaccine must show that it does not decrease the effectiveness of the other vaccines and does not result in higher rates of reactions.
Once vaccines become available to all children, systems are in place to monitor for reactions that were not apparent during the development stage. The Food and Drug Administration and the Centers for Disease Control and Prevention actively monitor vaccine safety.
Parents who delay or decline vaccination put their children at risk for preventable diseases.
Multistate outbreaks this year show that measles is just a plane flight from countries where vaccination rates are low; 63 of the 64 U.S. cases of measles occurred in unimmunized individuals.
The vaccine schedule recommended by the American Academy of Pediatrics and the CDC is designed to give vaccines when they would be most effective. Children are most susceptible to many diseases during the first year of life. Multiple vaccine doses over time are necessary to provide adequate protection. Delaying vaccines puts children and the community at unnecessary risk.
Giving the vaccines on the recommended schedule ensures children have immunity at the age when they are most susceptible to a preventable disease.
Regenstein raises concerns about the harmful effects of mercury preservatives in vaccines. There has never been any scientific evidence that a child was harmed by thimerosal, the mercury-based preservative that was used in vaccines in the past. To the contrary, large studies in Sweden, Denmark, the United Kingdom and the United States have shown no association between thimerosal-containing vaccines and autism.
A recent study looked at a California registry of autism and other neurological disorders. It compared the frequency of the diagnosis of autism before 2001 - the year thimerosal was removed from all vaccines except some influenza vaccines - with the rate of diagnosis after 2001. If thimerosal in vaccines caused autism, the rate should have fallen after the preservative was removed. In fact, the study showed that the rate increased, providing convincing evidence that thimerosal in vaccines does not cause autism.
More children are diagnosed with autism today than in the past. There are two major reasons.
First, the definition of autism has expanded. In the past, only the most severely affected children were called autistic. Now it is recognized that there is a spectrum of autism illness, with some children only mildly affected. It is still helpful to identify those children with mild symptoms because there are effective interventions that can help them reach their potential.
Second, children may be labeled autistic today who would have been called developmentally delayed or cited with behavioral problems a generation ago. A recent study showed that as the diagnosis of autism increased over a period of years, there was a corresponding and equal decrease in the diagnosis of those other conditions.
Parents are faced with a seemingly overwhelming amount of information about vaccines and autism. We encourage them to look for sources that are based on scientific evidence rather than anecdote and emotion. A list of useful Internet sites is provided for parents who desire more information on vaccines (see box).
The risks of the diseases that vaccines prevent are far greater than the unproven concerns about their safety. We encourage all parents to ensure their children's safety by immunizing them on time.
The writers are all pediatricians. Jay E. Berkelhamer is past president of the American Academy of Pediatrics and chief academic officer of Children's Healthcare of Atlanta. Harry L. Keyserling is professor of pediatric infectious diseases at Emory University School of Medicine. Walter A. Orenstein is professor of medicine and pediatrics at Emory University School of Medicine. Robert Wiskind practices with Peachtree Park Pediatrics. Among other Atlanta-area pediatricians and pediatric specialists who endorsed this column are Joseph Rosenfeld, A. Gerald Reisman, Joel A. Goldstein, Barbara M. Weissman, Howard S. Schub, Richard A. Levitt, Jonathan D. Winner, Paul M. Fernhoff, Barbara J. Stoll, Edward Salzberg, Jaquelin S. Gotlieb, Edward M. Gotlieb and Richard Weil.
