SPOKANE, Wash. -

According to the Washington State Department of Health, the state has the highest rate of schoolchildren not receiving vaccinations.

Six percent are not vaccinated compared to the national average of just 2 percent.

Health experts believe parents opting out of vaccinating their children is what's contributing to the recent rise in diseases like pertussis and measles.

Already this year, there have been more cases of pertussis –- or whooping cough as it's commonly referred to -– than in the entire year of 2011. The epidemic threshold for our state is between 57 and 125 cases, and in the first five months of the year there have been 1,008 cases of pertussis reported.

The disease is recognizable by the "whooping" noise children make as they gasp for air between coughing fits. Some infants will turn blue as they cough because they aren't getting enough oxygen. In some cases the disease can be fatal.

“You see them cough to the point of vomiting. It was a lot of nights of cleanup and drinking a lot of water and getting a lot of rest,” Julia Miller said.

At 3 and 5, both of Miller's children contracted pertussis.

“They did real well with it. They went through all the stages. It was at time as a parent you just think 'Aw man, am I doing the right thing?'” Miller said.

Her uncertainty was brief because Miller firmly believes that she did the right thing by not vaccinating her son and daughter.

“I know that I have had a couple of friends that have said, 'What are you thinking?' but at the same time I try to let them know this was our reason, based on these things and I outline them,” Miller said.

Miller's decision is rooted in her medical background. As a chiropractor, she sees our bodies as being created capable of fighting these diseases naturally:

“The goal is to sustain the integrity of the spinal column, the brain and the spinal cord. Being the central nervous system, it controls everything the body does, and if you can sustain that balance in immunity then you're going to have a more well-rounded immunity rather than a compromised immunity, which is sometimes led by vaccinations, which is what I've found in my research," she said.

Miller's concept is a tough one for most to grasp and that is why there is a contentious divide among parents who vaccinate and those who don't.

At the Spokane Regional Health District, there is no question that vaccines are safe and neccesary. Kristi Siahaya, the immunization outreach coordinator at the Health District, says everyone who can get vaccinated should.

“The hardest part of my job is talking to parents one-on-one, because they have stories and they truly believe what they see and they're really scared and I have to say as a new mom I was scared, too. It's a scary process to go through,” Siahaya said.

Armed with stacks of research, Siahaya can refute any argument against vaccination. She said there is no medical evidence that vaccines cause autism and that it's a one-in-a-million chance a child will die from receiving vaccines.

“We can relate some vaccines to injuries, possible seizure activity or some kind of systemic issue like that,” Siahaya said. “Fainting is the No. 1 thing that happens.”

Siahaya said the most troubling new trends are the diseases that are making comebacks.

“Pertussis is huge this year, and measles is seeing a huge rise across the country,” Siahaya said.

She said there are a few reasons why this is happening and cites kids not getting vaccinated as one. Unvaccinated children can expose the entire community to these diseases – including people who can't get vaccinated due to compromised immune systems.

Siahaya said waning immunity is also a problem. If you were vaccinated as a child, it doesn't mean you're immune as an adult. The vaccines can wear off, making you susceptible to a disease.

Even more alarming, adults with waning immunity that catch pertussis do not show classic signs of the disease, which means they can unknowingly pass it to a child.

“We had two children die of pertussis last year, two little kiddos, because they couldn't [be vaccinated], they were too young,” Siayaha said.

With pertussis and measles making comebacks, some doctors are closing their doors on patients who are not vaccinated.