More parents are choosing not to vaccinate their children in Arizona.

About 5.5 percent of sixth graders and kindergarteners have personal belief exemptions for at least one school required-vaccine, according to the most recent state figures.

That is a 0.5 percent increase from the previous year.

Charter schools have the highest rate of non-medical exemptions with nine percent — double the rate at public schools.

“We like to see 95 percent coverage rates or above for these vaccines, and that’s what’s really going to protect a community from a disease getting in,” said Jessica Rigler with the Arizona Department of Health Services.

“If you’ve got a school where one in 10 children are exempt, that school is ripe for a vaccine outbreak,” Rigler said.

Parents aren’t required to give reasons for not vaccinating their children when they fill out the form. Some don’t get all the vaccines done in time and fill out the form to make sure their child starts school. But Rigler says those “convenience” exemptions don’t account for the increase.

Instead, parents are choosing not to vaccinate their child most likely because of outdated information or inaccurate myths about possible side effects.

“People in higher income areas are often more likely to exempt their children,” Rigler said.

They also tend to be white and more highly educated, according to a study conducted by the state and researchers at the University of Arizona.

The authors suggest several reasons why exemptions are so pronounced at charter schools. It could indicate that parents with “alternate beliefs” about health care are more likely to enroll their children in those schools, or that charter schools put fewer resources into nursing staff.

In fact, schools in Arizona with more students who qualify for free and reduced lunches have the highest rates of coverage. This is probably because of intense efforts by public health agencies to get families access to affordable vaccines, the study says.

Students with personal belief exemptions are clustered in certain communities. In the metro area, most attend schools in north Phoenix and the East Valley.

In some cases, parts of Yavapai and Coconino Counties have exemption rates as high as 14 percent. These pockets are more susceptible to an outbreak because the herd immunity is so low.

ADHS has the coverage level for each school posted online.

Rigler says the state is educating parents about the dangers of not vaccinating, but any major changes to the rules will require new laws.