The state board of health adopted a new rule Wednesday requiring parents to submit a personal belief exemption every time they refuse a standard childhood vaccination, and at the beginning of every school year. 

Dr. Rachel Herlihy with the Colorado health department says before this rule, parents only had to file an opt out form once, when their child began day care or school.

"We certainly want choosing to vaccinate your child to be the easier option for parents than choosing to exempt your child," she explained.

But Denver mother Erika Roberg says choosing not to vaccinate her children was never convenient. Roberg says she suffered severe reactions to vaccines as a child and fears her children would experience similar responses if immunized. Roberg says she's  struggled to find a doctor who agrees.

"I had discussions with my doctor, and I had to deflect when he would tell me I was an idiot. Literally I’ve had doctors tell me that," she said. 

The new vaccine opt out rule takes effect next July.