Ravalli County Public Health Director Judy Griffin has seen what whooping cough can do to a child.
"I've seen a three-week-old baby with pertussis hospitalized and it's really incredible, and it really hits those babies hard," she says. "It's very ugly to see a baby struggling."
Griffin recalls the major outbreak that hit Ravalli County two years ago when dozens became infected and nearly 100 unvaccinated students were pulled from classes for three weeks. That was the first time in Ravalli County history that students had to be removed from school to protect the community through a process known as herd immunity.
"Basically, when you don't have an outbreak, the people who are vaccinated are actually protecting the kids or the people who choose not to be vaccinated," she says. "And then when this dips low and you have a lower immunization rate, then you're going to see more cases."
A growing sentiment against vaccination has officials like Griffin working to combat lower immunization rates and avoid a similar problem. The anti-vaccination contingent has been fueled by disinformation spread through the Internet—such as the debunked notion linking vaccines to autism—and drives some families to treat the shots as suspect or to reject them entirely.
Organizations like Shot Free in Montana and Montana Families for Health Freedom present the biggest local challenge to health officials. Shot Free in Montana claims the state's religious exemption law is lax enough to allow any family who does not believe vaccinations are in their child's best interest eligibility to file for exemptions. Out of 14,023 students enrolled in Missoula K-12 classes, 303 are listed as having religious exemptions from certain vaccines, with 89 more having medical exemptions.
Jon Ebelt, public information officer for the Montana Department of Health and Human Services, says the religious exemption statute does not provide information on specific religions or a verification procedure, but exemption forms clearly document the requirements. "We have no indication that false religious exemptions are being filed and we do not contact parents or guardians to verify," Ebelt says.
Montana Families for Health Freedom, which has a P.O. box listed in Florence, formed in 2008 and attempted twice to have Montana's exemption laws for vaccine regulations changed in the state legislature. After failing both efforts, Dewey Duffel, one of the group's founders, says the group now exists online only.
"In 2013 we basically monitored the proposed law changes and found none that were a significant threat to our goals," Duffel writes in an email. "Since then, MFHF has been inactive except for our web site presence which allows us to be contacted in case individuals want to ask a question about Montana exemptions or related matters."
Duffel says the group identifies as "vaccine-neutral," although its website directs visitors to articles advocating vaccine "liberation." One such site claims that present-day public health is generated from advances in sanitation and nutrition, and that vaccines, on the other hand, "introduce filth into a body."
The group's Facebook page, which was recently taken down, also posted links to anti-vaccine articles and memes. Last month, an article was posted claiming that vaccines can be implicated in the rise of autism. Last September, an image file was posted of a laughing child along with a caption implying that herd immunity is a myth.
Ellen Leahy of the Missoula City-County Health Department says dubious theories behind vaccinations can resonate deeply in parents simply trying to take care of their children.
"When you have a child there are so many things that you can think about that can cause fear in a parent, and the parent of course wants to do the very best," she says. "So when they continue to perpetuate the completely disproven link between vaccination and autism, that's completely fear-based and they're not up to date on the data and the science on that."
Griffin says anybody disputing the existence of herd immunity will be told different by simply consulting an epidemiologist.
"The point I want to put across is that if you're vaccinated and you come in contact with pertussis, you're not going to be as sick as if you have never been vaccinated before," she says. "The anti-immunization people are gonna think, 'Well, yeah, look at all these people that still got it after they've been vaccinated,' but the point is that you're not going to be as ill as if you have never been vaccinated before."
The problem for physicians is that to effectively vaccinate, patients must come to them. Those convinced of a problem with vaccinations may never have an opportunity to discuss the issue.
"When people come here they've pretty much decided to get it," Leahy says, "or they maybe want to get them on a slower schedule and so we talk with them about how to get it on a slower schedule if that makes them more comfortable."
Missoula County's most recent outbreak of whooping cough is not officially over, as the incubation period from the last confirmed cases has not passed. This winter officials counted eight cases, three of which were contracted by students at Hellgate High School. Leahy says some of those cases may suggest that herd immunity in Missoula County is weakening. Nationally, cases of measles, mumps and pertussis, long regarded as bygone illnesses thanks to widespread vaccination, have seen resurgences in areas where vaccination rates have dropped.
"You actually need really good herd immunity to be protective to the public at large," Leahy says. "We actually have some fully immunized children that have had positive tests for pertussis. They have not been very ill, which is good."
Missoula County Public Schools Health Services Supervisor Linda Simon says Missoula is lucky to avoid an outbreak on the level of Ravalli County's two years ago. Nonetheless, she notes that pertussis infections have increased during her 16-year-long career in Montana.