I’ll try to address some of the excellent questions that were asked and points that were raised.
Regarding Jennifer’s comment that the stated previous incidence of autism of 1 in 10,000 children is inaccurate: You’re right. I’ll make sure not to use that statistic in the future. Thanks for pointing that out. As you note, the incidence is closer to 1 in 2,500.
Regarding the financial impact of vaccines: The CDC always performs a cost-benefit analysis to determine whether the anticipated savings in healthcare costs and indirect costs (i.e., lost time from work) justifies the price of a vaccine. But I suspect that your question is broader than that. I’ve heard a Harvard economist (Bloom) describe the impact of vaccines when they first enter a developing country. He makes the point that family sizes start to get smaller and economies improve. His point being that not only does wealth make health (although you could argue that one in the US) but that health makes wealth.
Regarding autoimmunity triggered by vaccines as a possible cause of autism: It is certainly true that infections can trigger autoimmune responses (e.g., streptococcal infections as a cause of rheumatic fever, campylobacter infections as a cause of Guillain Barre Syndrome, or Borrelia burgdorferii [Lyme disease] as a cause of chronic arthritis). However, there remains no clear evidence that vaccines induce autoimmune responses. Probably the best example is Lyme disease, where arthritis appears to be mediated by T cell responses to the outer surface protein OspA, the same protein contained in the vaccine. But two large studies have clearly shown that Lyme vaccine does not cause chronic arthritis. The point being that vaccines are generally too wimpy to meet the four criteria necessary for induction of autoimmune responses: First, autoreactive T or B cells must be present. Second, self-antigens must be presented to the immune system in quantities sufficient to cause autoreactive cells to divide and mature. Third, additional signals such as cytokines are required to activate autoreactive T and B cells. Fourth, regulatory T cells must fail to control destructive autoimmune responses. Only when all of these conditions are met will expansion and activation of autoreactive lymphocytes and progression to autoimmune disease occur. No vaccine has been shown to meet these four criteria. Finally, pathogenetic studies of the brains of autistic children have consistently failed to show evidence that the disorder is immune mediated.
Regarding scientists standing up for good science: I think that scientists have been reluctant to enter the vaccine-autism fray for many reasons. The skills required to perform good science, write scientific papers, and present data in front of a scientific audience are different from those required to describe science to a reporter or reduce complex issues to sound bites on television. And standing in front of a national television audience is not a natural act. Also, to bastardize Dickens, the media is an ass. Scientists actually believe in truth. It make take weeks or months or years to get to that truth, and one may never get to it, but I think we believe that it’s there. And although I have encountered several people in the media who really do want to get it right, most are just interested in holding the whetted finger to the wind and promote controversy even when a scientific controversy doesn’t exist. All under the journalistic mantra of balance, when public education is better served by perspective. For many scientists, this is a very hard process in which to participate.