Whooping cough is at epidemic levels in Colorado, but parents can opt students out of school vaccination requirements with a simple signature at registration.

Friday, a bill was introduced at the Statehouse that would require parents to take an online module or provide proof of speaking with a healthcare professional before opting their children out of a vaccine.

"Vaccine-preventable disease really impacts our whole community, especially our youngest," said Stephanie Wasserman, executive director of Colorado Children's Immunization Coalition. The group partnered with state researchers to look into the use of personal-belief exemptions that allow parents to opt out of vaccines in 2013 and turned their work into new legislation.

In the 2012-13 school year, the state estimates parents opted 3,000 kindergartners out of vaccinations. About 93 percent of those children were opted out because of personal beliefs, according to a state survey. In Colorado, parents can also opt out their children for religious and medical reasons.

The bill aims to make sure parents understand possible impacts of opting out of vaccinations and prevent parents from signing the form out of convenience, Wasserman said. Colorado is one of 20 states that give parents the personal-belief option. The state ranks sixth in the nation for parents who take that option.

The bill would also require schools and early child care centers to publish immunization rates so that parents can make health decisions about where to send their children, Wasserman said.

Currently, schools collect the immunization records or exemption signatures for every child, but do not have to make the immunization rates available to parents.

This information would be especially important to parents of children with autoimmune disorders or those who have cancer and are at much greater risk, said Rachel Herlihy, the deputy director of the Division of Disease Control & Environmental Epidemiology for the state.

If the bill is signed into law it is currently written to take effect on July 1, 2015.

Of even greater concern, to Dr. James Todd, director of epidemiology, clinical outcomes and clinical microbiology at Children's Hospital Colorado, is the percentage of toddlers who aren't vaccinated on time.

In Colorado, more than 20 percent of children 19 to 35 months did not receive all the vaccine doses recommended in 2012, according to the National Immunization Survey.

This is concerning because the majority of children who are hospitalized with vaccine-preventable disease are under 4 years old, according to a study that Todd co-authored.

The problem is exacerbated because generally parents who choose not to opt out send their children to the same schools, he said. This leads to pockets of higher risk.

The study also presented a strong financial argument for greater vaccination.

In 2012, more than 414 cases of vaccine-preventable disease racked up $26.6 million in hospital fees. About 300 of these were whooping cough cases.

Todd said he included the cost of these diseases because lawmakers must weigh the fiscal impact.

"There are really significant economic consequences of not vaccinating," he said.

Educating parents about vaccinations is a priority.

Vangi McCoy, coordinator at Motelores Early Childhood Council, found the legislation reasonable and doesn't think publication requirements put undue pressure on child centers because they're already required to track immunization records.

The bill, in her opinion, balances preserving personal choice and making sure parents are informed.

"We, as parents, don't want it dictated what we do with our kids," she said.

Mancos school nurse Karen Blaine has worked for six years to ensure that parents are informed about their decision.

The school is 100 percent compliant, meaning every child has up-to-date vaccinations or their parents have turned in exemption forms. A few exemptions are unavoidable because some children are allergic to eggs used in vaccines.

She said it is tempting to sign an exemption.

"A lot of people will just sign that exemption so they don't have to find immunization records," she said.

Blaine is required to inform each parent before they sign an exemption. But she takes the issue to heart after witnessing cases of polio in Africa. She works to connect Mancos parents to the appropriate resources including the health department and the Mancos clinic.

She also tracks down records so students' records will be updated.

She expects compliance to be easier to achieve now that Mancos has a preschool because she can start talking to parents earlier about the requirements.