Experts Weigh in On US Government's Vaccine Injury Ruling

On the other hand, some believe the decision may open the door to more research into potentially vulnerable subpopulations that could be at increased risk of sequelae from vaccines.

On March 6, the parents of Hannah Poling announced that federal health officials ruled a series of 9 simultaneous vaccines administered to their daughter when she was 19 months old worsened an underlying mitochondrial condition that ultimately led to a diagnosis that included "features of autism spectrum disorder." As a result, the family is being compensated from the National Vaccine Injury Compensation Program.

A news release from the US Health Resources and Services Administration (HRSA) states that while the government cannot publicly disclose details of a specific case without the consent of the individuals involved, it "has reviewed the scientific information concerning the allegation that vaccines cause autism and has found no credible evidence to support the claim.

"HRSA has maintained and continues to maintain the position that vaccines do not cause autism and has never concluded in any case that autism was caused by vaccination."

Open to Misinterpretation?

Despite this reassurance, experts are concerned that the ruling, which they say is based on a rare case with rare circumstances and a rare outcome, will be misinterpreted as an acknowledgment that vaccines cause autism.

According to Joel Bregman, MD, chair of the committee on developmental disabilities of the American Psychiatric Association (APA), it is known that this child has a rare underlying mitochondrial condition and received a number of vaccines at once, which is also atypical, and subsequently developed autismlike symptoms.

"This is a unique set of circumstances that should not be extrapolated to the rest of the population," Dr. Bregman told Medscape Neurology & Neurosurgery. "Even though there is a great deal of research — not just in the United States, but in other countries as well — there is no evidence linking childhood vaccines to autism. We are very concerned the public may misinterpret this decision," he added.

Decline in Immunization Rates

Wendy Roberts, MD, codirector of the autism research unit at Toronto's Hospital for Sick Children, in Ontario, agreed.

"The confusion here is there may be an occasional child who has a very bad reaction to immunization — statistically it is about 1 in a population of 100,000. But as soon as parents hear of 1 case, not understanding the 1-in-100,000 statistic, they immediately think all immunization is bad," Dr. Roberts said in an interview.

The consequence of this is a potential decline in immunization rates, which poses a serious public health threat. According to Dr. Roberts, prospective research undertaken by her team indicates this is already happening.

"We know that our vaccination uptake has gone down at least 3% to 4%. But in some sectors where individuals have a family history of autism, it has dropped by 30% to 40%," she said.

Dr. Roberts added that she is concerned the US government ruling will contribute to a further decline in immunization rates.

The McCain Factor

She noted in particular that she was very concerned by media reports quoting US Republican presidential candidate Sen. John McCain that thimerosal, the mercury-based preservative used in vaccines, was strongly linked to autism.

"When someone in his [McCain's] position makes those kinds of strong statements, it is such a misuse of power. Canada has led the way in removing preservatives from vaccines, and our rates of autism are just as high as anywhere else," she said.

Both Drs. Bregman and Roberts made the point that there are a whole generation of people who have no experience with outbreaks of infectious diseases such as measles and their potentially devastating consequences.

"We're not just talking about a rash or a fever. Many of these diseases are associated with significant mortality and adverse consequences, including brain damage," said Dr. Bregman.

More Research Warranted?

Robert Hendren, president of the American Academy of Child and Adolescent Psychiatry (AACAP), said his organization is also concerned that the public may interpret the decision as a blanket attack on or condemnation of population-based immunization.

"This is a complex issue, and we are expecting the lay public to sort it all out, and so there is a possibility that it will be simplified and seen as a message that vaccines are associated with autism," he told Medscape Neurology & Neurosurgery.

While there is no doubt about the immense benefits of population-based immunization, Dr. Hendren added, the ruling may provide the impetus to conduct more research into specific subpopulations of individuals who, for whatever reason, may be at greater risk of an adverse reaction to vaccination.

If such subpopulations do exist, said Dr. Hendren, these individuals would be unlikely to show up in large, population-based studies.

For its part, the American Academy of Pediatrics released a position statement about the Poling case stating that the academy is seeking access to "official documents in the case, so medical experts can examine the science and consider whether it raises implications for other children."

In its statement, the HRSA says it will present its views "on the allegation that vaccines cause autism in an omnibus autism proceeding in May."