The number of newly diagnosed cases of autism continues to rise while researchers strive to find the cause. Described as a spectrum disorder, autism includes victims severely disabled as well as those who can be described as highly intelligent. What they all have in common
is a combination of three traits. They may have a defect in social behavior with an inability to hold eye gaze; a defect in language or no language ability at all; and an increase in repetitive stereotyped behavior, such as flapping or other forms of self-stimulation.

Some autism advocacy groups have long held that one cause of autism is the vaccinations required for school entry. In the United States, children are vaccinated against at least nine, and in some cases many more, diseases, with immunization beginning as early as birth or six weeks of age. Immunization for some diseases requires multiple doses, with boosters given after a period of years.

Autism advocates point out that, in many cases, patient development may have progressed normally until the age of about two, with regression seeming to follow the vaccinations given at that age. Initially, some autism advocates thought that the cause might be the trace amounts of thimerosal mercury used as a preservative in some vaccines. Since 2001, all thimerosal has been removed from childhood vaccines with no appreciable decrease in the rate of autism. It is the same rate found in other countries where thimerosal continues to be used.

In fact, a recent study done at the University of Rochester and published in the February issue of the journal Pediatrics showed that babies expel thimerosal mercury faster than was previously thought, giving them little opportunity to build up to a toxic level. They actually expel thimerosal mercury 10 times faster than methyl mercury, the type associated with eating contaminated fish.

Is There a Genetic Component?

Scientists believe that there are probably a number of factors relating to the causes of autism, but studies of twins show that genes may play a major role. In May, it was reported in the Journal of Medical Genetics that a gene called contactin 4 is responsible for making proper network connections within the brain. Each child should have two copies of the gene, but disruption could account for as many as 2.5 percent of the autism cases, a significant number according to study leader Dr. Eli Hatchwell of Stony Brook University Medical Center in New York. However, he states that there are most certainly additional causes.

Another gene, identified by researchers at Johns Hopkins University School of Medicine and the University of Illinois at Chicago, is discussed in an online version of the American Journal of Human Genetics. That gene plays an important role in brain development and places infants at increased risk when inherited through the mother.

A teleconference by the Center for Disease Control was held in March in response to media questioning the recent announcement of a settlement reached by a federal vaccine compensation court awarded to Hannah Poling. Hannah’s father, Dr. Jon Poling, was a neurology resident at Johns Hopkins Hospital in 2000 when she received five shots against nine infectious diseases. She suffered a fever two days later and then behavioral regression, eventually receiving a diagnosis of autism.

Or Is It the Vaccine?

Intensive subsequent testing found that she had a disorder of the mitochondria not thought to be caused by vaccines. These are a group of genetic disorders involving disturbed functioning of the mitochondria or “powerhouse of the cells.” When children with these disorders suffer stress, they are unable to meet the energy needs of the developing brain and suffer regression of neurological abilities. These disorders are technically very difficulty to diagnose and scientists are still unsure of the prevalence in the population.

Dr. Thomas Iselin of the National Institute of Mental Health participated in the March teleconference about vaccine safety. He stated, “There are some forms of autism that will occur as part of other…genetic diseases; fragile x, tuberous sclerosis. And there are a few that have autism as part of an overall syndrome. And there are some cases of autism in which we find genetic lesions. But, in fact, most cases are probably due to both genetic and environmental factors.”

Knowing that some vaccines can prompt a high-fever response leaves some parents uneasy about vaccinating their children, and many now claim exemption from the law. Nationwide, 90 percent of those children eligible for vaccination receive their shots. All states allow medical exemptions for those children with medical certification that they could be harmed by vaccines. Some states also allow religious exemption, but now 20 states allow some kind of personal exemption. Fear of autism may fall into that category, and public health officials fear that as rates of immunization fall, diseases once almost extinct will once again surface, causing significant outbreaks.

When most people are immunized, it is the non-vaccinated population at risk of developing disease. These same children, should they get the disease, can then present a very real risk to those who have been vaccinated, because even vaccination doesn’t provide 100 percent immunity to all diseases. Some serum may have been improperly stored, given inaccurately, or some individuals may not produce a vigorous enough antibody response. Babies under six weeks are generally too young to receive vaccination, and live vaccines like MMR and Varivax are not given until the age of 12 months. While circulating maternal antibodies may provide some protection, there remains a long period of possible exposure. Recent outbreaks in American cities of measles, mumps, varicella and pertussis prove that significant risk of disease remains.

Public health officials point to the fact that childhood diseases are nearly a thing of the past. Immunization is one of the greatest health initiatives of the last century and a hallmark of developed nations. Even so, some parents may well remain wary until it can be proved to them that their child will not suffer neurological damage in the quest of the common good.

Christine Contillo, RN, BSN, has worked as a nurse since 1979 and has written extensively for various nursing publications, as well as The New York Times.