by Amy Spangler
February 05, 2010

Do vaccines cause autism?
The controversy surrounding vaccines and autism dates back to 1998 with the publication of the now retracted paper by Andrew Wakefield titled, “Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children.” The authors theorized that the measles-mumps-rubella (MMR) vaccine causes a series of events that result in the development of autism. The study describes 12 children with neurodevelopmental delay (eight with autism). The author notes that each of the eight autistic children was diagnosed with autism within 1 month of receiving the MMR vaccine.

Critics argued that the MMR vaccine is administered to nearly all children at a time when many children are diagnosed with autism. Therefore the observation that some children with autism recently received the MMR vaccine is expected. In addition, only vaccinated children were included in the Wakefield study. To determine whether the MMR vaccine causes autism, both vaccinated and unvaccinated children must be studied. Furthermore, in each of the eight autistic children, symptoms of autism were observed before, not after, the presence of gastrointestinal symptoms, thus refuting the authors’ claim that autism is a consequence of gastrointestinal inflammation. Wakefield published a second paper in 2002, in which he examined the relationship between the measles virus and autism. Again critics cited a number of flaws.

While the two studies by Wakefield suggest a causal link between the MMR vaccine and autism, five additional studies conclude the opposite. Researchers found no difference in the age of diagnosis of autism in vaccinated and unvaccinated children; the onset of regressive symptoms of autism did not occur within 2, 4, or 6 months of receiving the MMR vaccine; and despite a dramatic increase in the number of reported cases of autism, the percentage of children that have received the MMR vaccine has remained the same. Data from a Danish study show that rates of autism continued to rise despite the removal of thimerosal from all vaccines in 1992.

The result of a critical review of the data was also published in Pediatrics in 2004. Twelve publications met the selection criteria, 10 epidemiologic studies and two pharmacokinetic studies. The authors concluded that the data did not support the claim that thimerosal-containing vaccines cause autism.

No link between thimerosal-containing vaccines and autism
In 2000, in response to a request from the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH), the Institute of Medicine (IOM) established an independent expert committee to evaluate the data and determine whether vaccines cause specific health problems.

The Immunization Safety Review Committee published a series of reports between 2001 and 2004. The committee concluded that neither thimerosal-containing vaccines nor the MMR vaccine is associated with autism.

A second IOM committee met in February 2005, composed of different scientists. According to Committee Chair John C. Bailar III, “concerns about access and transparency have accompanied the development and functioning of the Vaccine Safety Datalink data-sharing program, and consequently some people’s trust in the reliability of findings from VSD studies has eroded. Taking steps to improve the independence, transparency, and fairness of VSD procedures will help enhance confidence in the data sharing program and in research based on this important tool for evaluating vaccine safety.”

The Vaccine Safety Datalink is a large, linked database of patient information that was developed jointly by CDC and several private managed care organizations in 1991. It includes data on vaccination histories, health outcomes, and characteristics of more than seven million patients from eight participating health organizations. Researchers from the CDC and the managed care groups have used VSD information to study whether health problems are associated with vaccinations. The subsequent VSD data-sharing program was launched in 2002 to allow independent, external researchers access to information in the database.

Are vaccines safe?
Vaccines have significantly reduced, and in some cases eliminated, many childhood diseases. In the past, polio, rubella, measles, diphtheria, tetanus, chickenpox, and pertussis (whooping cough) were among the diseases that caused thousands of deaths each year. Today, as a result of immunizations, these diseases rarely occur. A widespread decline in immunizations would lead to outbreaks of serious diseases that now occur rarely.

Any discussion of vaccine safety must include a discussion of the benefits of immunizations as well as the risks. All vaccines have possible side effects. Most side effects are mild and include fever, rash, and tenderness or swelling at the injection site. Some side effects can be severe. For example, the pertussis vaccine can cause persistent crying, high fever, and seizures. While these side effects seldom cause permanent damage, they can be frightening for parents. But if you compare the potential risks of vaccines and the established risks of disease, vaccines, with few exceptions, are the safer choice for both children and adults.

What parents need to know:

• Few things in medicine work 100 percent of the time.
• Few things in medicine are risk-free.
• Researchers are working continually to improve the safety of immunizations.
• A decline in immunization rates will lead to an increase in disease.

To illustrate this fact: In 1974, when 80 percent of Japanese children were vaccinated for pertussis (whooping cough), only 393 cases of pertussis occurred and none of the victims died. The following year information was circulated that the pertussis vaccine was no longer needed and that is was unsafe. By 1976 only 10 percent of Japanese infants were vaccinated and in 1979 over 13,000 cases of whooping cough were reported along with 41 deaths. These are the risk/benefit ratios that parents as well as professionals must consider.

The only time it is safe to stop giving immunizations is when a disease has been eradicated worldwide.

Only a parent of an autistic child can fully understand the anguish that comes from not knowing autism’s cause. But no amount of fear or frustration justify an abandonment of science.

Editor’s Note—January 5, 2011
The first in a series of articles by journalist Brian Deer showing the extent of Andrew Wakefield’s fraud and how it was perpetrated was released today. Drawing on interviews, documents, and data made public at the General Medical Council hearings, Deer shows how Wakefield altered numerous facts about the patients’ medical histories in order to support his claim; how the Royal Free Hospital and Medical School in London supported Wakefield in his efforts to capitalize on the ensuing fear; and how Deer’s early concerns about the validity of the study were ignored by key individuals.