Last week, the special panel of the Vaccine Injury Compensation Program (VICP) ruled that there is no link between vaccines and autism. The decision has re-ignited the hot debate over the causes of autism, with some groups placing the blame squarely on thimerosal-containing vaccines and others who believe that a combination of factors, both genetic and environmental, are responsible. Many studies conducted in the United States and abroad have shown that there is no significant link between vaccines containing thimerosal, such as the measles, mumps and rubella (MMR) vaccine, and autism. The masters on the special panel placed great significance on the results of these studies, noting that the scientific evidence showing that there is no link was more persuasive, and thus held that the plaintiffs were unable to support the link by a preponderance of the evidence.
The groups who support the vaccine-autism link point to increases in the incidence of autism as a result of using thimerosal-containing vaccines. Opponents argue that the claimed increase is not due to an increase in the incidence of autism, but rather that more disorders are now included under the umbrella term “autism,” that the age at which autism can reliably be diagnosed is the same as when MMR vaccinations are received, and that health care professionals now routinely test for autism at well-child checkups.
Fear of the vaccine-autism link has caused many parents to refuse to have their children immunized. Every state requires schoolchildren to be vaccinated but allows exemptions for medical reasons such as allergies to vaccine components; most states also allow exemptions for religious reasons. Parents in the so-called “anti-vaccination movement” generally can take advantage of either of these exemptions to avoid having their child vaccinated. However, in those states which routinely grant such exemptions, the rates of pertussis and measles are on the rise. The problem with increases in the number of unvaccinated children is that they become a reservoir for the bacteria and viruses that cause life-threatening childhood diseases. According to the concept of herd immunity, as long as the majority of children are vaccinated, these diseases can successfully be kept in check. It is only when a critical number of children are unvaccinated that the rates of vaccine-preventable diseases rise; for some diseases, this number is surprisingly low.
It is truly unfortunate that there is no easily identifiable and preventable cause of autism, such as thimerosal-containing vaccines. The panel’s decision should be yet another indication that research into the causes of autism should focus on a more likely area, such as the interplay between genetics and the environment.
Comments
Post new comment