One of Republican presidential contender Donald Trump's most brazen moments at the Sept. 16 candidates' debate came during an exchange with fellow GOP nomination hopeful Ben Carson.
When asked by debate moderator Jake Tapper whether Trump should stop publicly linking vaccines to autism, Carson—a pediatric neurosurgeon—responded "[Trump] is an OK doctor, but the fact of the matter is, we have extremely well documented proof that there's no autism associated with vaccines."
Trump doubled down on his belief vaccinations have helped push autism to "epidemic" levels in the past 25-30 years.
"It has gotten totally out of control," he said.
The exchange between Trump and Carson highlighted the ongoing rift between so-called "anti-vaxxers" and the research and evidence debunking claims vaccines cause neurological conditions such as autism.
According to a report released by the Centers for Disease Control in late August, nowhere in America is that rift wider than Idaho, which had a 6.5 percent childhood vaccination exemption rate during the 2014-2015 school year.
Figures like those have stakeholders across the Gem State wringing their hands.
"We believe we can do better," wrote Idaho Public Health Medical Director Dr. Christine Hahn in a blog post published on the Idaho Department of Health and Welfare website following release of the CDC report.
Resistance to childhood vaccination began in earnest in 1998, when Andrew Wakefield, a gastroenterologist at the Royal Free Hospital in London, published a paper voicing concerns about a possible link between the measles, mumps and rubella (MMR) vaccine and autism. Though medical researchers long ago discredited the MMR-autism link, they have struggled to regain public confidence in a variety of vaccines—to the point where the medical community and anti-vaxxers are not speaking the same language.
"You need to stop using the word 'immunization.' We don't say 'immunization.' Vaccines don't immunize anything," Ingri Cassel, of north Idaho-based anti-vaccination group Vaccination Liberation, told Boise Weekly in 2011.
When it comes to national childhood vaccination statistics, Idaho is an outlier. The state with the next highest total exemption rate is Colorado at 5.4 percent; the lowest is Alabama, at 0.7 percent. California's total number of exempted students is 13,993, which dwarfs Idaho's 1,432, but Idaho's total exemption rate is more than 2.5 times the Golden State's—and the rate increased by 0.1 percent between the 2013-2014 and 2014-2015 school years.
CDC delved further into the data, breaking down total state-by-state exemptions by those based on "philosophic," religious or medical objectives (90 percent, 9.5 percent and 0.3 percent in Idaho, respectively), as well as those parents claiming an exemption during school registration because their children were behind on their vaccination regimen.
"The sliver of good news is that 90 percent of Idaho kids are covered," said Idaho Department of Health and Welfare Public Information Officer Niki Forbing-Orr. "Over the years, Idaho's vaccination rate has been trending upward."
In Bonner County, just north of Cassel's homebase in Spirit Lake, the childhood vaccination exemption rate hovers at 20.6 percent. Dana Williams, a registered nurse at the Lake Pend Oreille School District, has daily conversations with parents who don't want their children to receive vaccines, and the topic of unvaccinated children comes up at every staff and administration meeting she attends.
Williams described an instance in which a parent filled out an exemption form other than the one mandated by the state because it implied by not vaccinating his child, he wanted his child to become ill.
"I said, 'It doesn't say that. It says you're making a choice based on what you feel, philosophically, that you don't want your child to have vaccines,'" Williams said.
More than a decade has passed since an outbreak of a vaccine-preventable disease in the school district, despite several near misses—outbreaks in neighboring counties and states. According to Williams, time has eroded the cultural memory of when diseases like smallpox and measles ran rampant.
"I remember taking a polio vaccine when I was in grade school—you know, the sugar cube, so that tells you how old I am—but there hasn't been polio here for a long time, so people don't think it's that bad of a disease," she said.
Williams serves all 11 schools in the Lake Pend Oreille School District, and she said unvaccinated children pose a critical public health threat there. She said the principle of "herd immunity"—vaccinated children are a shield against disease for unvaccinated children—isn't present in Bonner County. Herd immunity also buys health care workers time in the event of an outbreak. For instance, it takes five to 10 days for the obvious signs of a measles infection to appear but in that time, a sick child can spread infection to her classmates.
"The thing that I don't like about it is, we're asking parents to vaccinate their children. They're in classrooms of 20 to 30. One kid gets sick, and you know what? A bunch of others can get sick. That's why we want them to get vaccinated," Williams said. "It's bothersome to me because I try to talk to parents and let them voice their feelings, and I try to explain to them that, you know, you can die from this. Sometimes, they just don't get it."
Correction: A previous version of this article incorrectly identified Niki Forbing-Orr as a public information officer for the Central District Health Department, not the Idaho Department of Health and Welfare. We regret the error.