A Colorado state Senate committee passed one of the most intensely debated bills of the legislative session, a measure requiring parents to fill out a state form to exempt their children from child vaccinations.
After five hours of testimony, House Bill 1312 was sent to the Senate floor on a 4-3 party-line vote by Senate Finance Committee.
Supporters said the state needs a better way to track exemptions and, more importantly, to encourage more people to immunize their school children.
The Centers for Disease Control has recorded more than 700 cases of measles in 22 states, including Colorado.
"This is a really important bill," said Sen. Julie Gonzales, D-Denver, a sponsor of the legislation. "We are in the middle of a public health crisis."
The House saw committee meetings and floor debates for hours deep into the early morning hours over the last month.
The Senate didn't have that kind of time, with Friday's midnight adjournment looming over all legislative discussions at this point.
Hundreds of parents marched, carried signs and yelled on the second floor of the Capitol waiting for the hearing to begin Wednesday night.
Many of the parents opposing the bill say they fear potential harm to their children from vaccinations. Experts say vaccination is almost always safe and that the possible spread of disease poses a greater risk.
Sen. Lois Court, chair of the Senate Finance Committee, limited testimony to four hours. The bill was introduced in the Senate Wednesday then scheduled for a committee hearing a few hours later.
The race against the clock is on for the bill to make it through at least two floor votes in the Senate before the legislative session's adjournment at midnight Friday.
Sen. Owen Hill, R-Colorado Springs, who opposed the bill, urged his colleagues to reconsider and hear out everyone who wanted to testify on the bill.
"It's is a big deal," he said. ""We scheduled this committee at the last minute, and a lot of these people had to drop everything they were doing to come up here."
The bill would require parents or guardians who wish to withhold some or all vaccinations to file the standardized form with the state health department.
Though exemptions would be harder to obtain, the bill doesn't take away any exemptions for medical conditions or personal beliefs.
Opponents of the bill said creating such a database is a form of government intimidation and poses risks to medical privacy, though an vaccination registry already exists.
Parents notify their schools now if they want an exemption, but proponents of vaccinations said that creates an incomplete record of immunization rates.
Theresa Wrangham, executive director of the National Vaccine Information Center, said the bill and the logic behind it were flawed.
"Passage of this bill would equate to legalizing state-sanctioned punishment, discrimination and an invasion of privacy of a small minority who exempt," she told the committee.
Supporters brought up the measles outbreak and called it a shared public responsibility to deal with it by increasing vaccinations.
"This is an urgent public health issue that directly affects my patients," said Stephanie Bourque, a pediatrician at Children's Hospital Colorado. "With the current measles outbreak, it's a matter of when not if we see cases in Colorado."