With time beginning to run out on the four-month legislative session, the Colorado House debated a bill Tuesday to beef-up school immunization exemptions.

The goal of House Bill 1312 is to discourage people from opting out of vaccinations, while still preserving the option for those who have medical reasons or objections for religious reasons, or who believe that the government shouldn’t have any say in parents’ decisions involving their children.

Rep. Kyle Mullica, D-Northglenn, the bill’s House sponsor, said it preserves parental choice.

“What this bill does is formalize the process,” he said.

Rep. Mark Baisley, R-Roxborough Park, passed along information he said he heard from a friend of his who’s a doctor: Undocumented immigrant children flooding across the southern U.S. border are unvaccinated and bringing in diseases.

That offended Rep. Yardira Caraveo, D-Denver, the granddaughter of immigrants and a pediatrician who works with immigrant children. 

She said it’s not immigrant children she sees denying vaccination requests, but upper middle-class white families, most often.

Baisley tried to make amends, saying he meant no offense or insult toward immigrants.

“When they come at the level they’ve been coming in lately, that causes the numbers to change,” he said of undocumented children. “That’s not a criticism. That’s just an observation.”

The bill’s supporters argue that Colorado schools are at risk of an outbreak of a contagious illness, pointing to measles cases in other states.

Rep. Susan Beckman, R-Littleton, said she vaccinated her kids and would do it again, but she’s not comfortable having the state pressure other parents into the decision to do it.

“There is no freedom more fundamental than the right to be free to decide what risks you’re willing to take with your life and the lives of your children,” she said. “… Where there’s risk, there should be choice.”

Beckman opposed the bill as a member of the House Health and Insurance Committee, which heard nearly 14 hours of testimony from hundreds of parents, advocates and medical professionals on each side last week.

RELATED: Bill to increase childhood vaccination in Colorado passes House committee (VIDEO)

The legislation passed the House on voice vote Tuesday. It now has to pass a recorded roll-call vote in the House before it can move to the Senate and start over. The 120-day session is set to adjourn next week. Democrats, who generally support the bill, have the majority in both chambers.

The standardized form for parents to fill out is aimed at helping the state track of vaccination rates and exemptions. 

Under current procedures, exemptions are granted by local schools without the state’s involvement.

The bill also calls on health care providers and public agencies to tell parents or guardians they can exempt their child from state immunization data collection, if they claim a medical or religious exemption.

The state health department would be required to develop educational materials on immunizations and distribute them to doctors and health care facilities.

The bill, however, doesn’t subject health care providers to regulatory sanctions for not complying with the data-reporting system.

The Colorado Department of Public Health and the Environment says vaccination rates seem to be improving, based on incomplete data, climbing as high as 95% for five of six vaccinations required for school-aged students last year.

Rates vary widely by school, however, and Chalkbeat Colorado found that in some schools, immunization rates are 50% or less.

The vaccination debate is being waged in other state legislatures and in Washington, D.C., as well. 

The Washington state Senate passed a bill last week to make it harder to exempt children from immunizations for measles, mumps and rubella, as the state weathers one of its worst measles outbreaks in decades.