The term Amish anomaly was coined by Dan Olmsted, who asserted that he could only find three Amish autistics after searching in Lancaster County, Pennsylvania and that two of them were vaccinated.
Contents
Background
In his columns, Olmsted quoted Dr. Frank Noonan as saying, "You'll find all the other stuff, but we don't find the autism. We're right in the heart of Amish country and seeing none, and that's just the way it is."
Criticism
Ken Reibel, of the blog Autism News Beat stated that, "The idea that the Amish do not vaccinate their children is untrue.” Dr. Kevin Strauss, MD, a pediatrician at the CSC, when contacted by Reibel, said that Olmsted never visited the CSC or spent much time in Lancaster County.
Further criticism of Olmsted's reporting comes from David N. Brown, who states that "In March 2006, Drs. Kevin Strauss, Holmes Morton and others documented 9 autistic Amish children, which could raise the autism rate of the Lancaster Amish community Olmsted supposedly investigated to almost 1/5,000 which is still a fraction of the US average of 1/68 The statement that autism doesn't exist in Amish populations generally is an exaggeration, though the rate is a small fraction of that in the surrounding population.
Vaccination rates in Amish communities
A 2007 study in the official journal of the American Academy of Pediatrics on an Amish population in Holmes County, Ohio found that 60% had vaccinated at least some of their children, and 68% had given all their children at least 1 vaccination.
Similarly, a 2006 study by researchers from the CDC, based on a survey sent to residents of the largest Amish community in Illinois, concluded that the Amish may not object to vaccines very often, and that when they do so, it may not be for religious reasons.
Amish incidence of measles
In 2014, a measles outbreak with more than 360 cases, started after Amish travelers to the Philippines contracted measles that year and returned home to rural Knox County. From there, the highly contagious disease spread quickly because of a lower rate of vaccination among the Amish. The county had 54 cases of measles and one hospitalization. Most of its Amish were already vaccinated before the outbreak. The disease was introduced by three unvaccinated missionaries, who had traveled to Philippines (which was itself experiencing a major outbreak).
Alternative explanations
There are alternative explanations for the low Autism/ASD rates in the Amish communities. Autism is thought to have many genetic or epigenetic correlations. If prevalence of ASDs did vary in a relatively isolated, closed population such as Amish communities, it could be explained by gene pool variations compared the general population. Similarly to Amish having statistically higher rates of some conditions (such as dwarfism, Angelman syndrome and metabolic disorders), they could also be expected to have lower rates of some others.