After hours and hours of debate and sessions that went to the early morning hours, the Colorado Senate effectively canned a bill to beef up the state’s vaccination reporting requirements.

Senate Majority Leader Steve Fenberg of Boulder announced on the Senate floor Thursday afternoon that the bill would be postponed until Friday, effectively killing it.

Legislative rules require that the floor debate on a bill, called second reading, and a roll call vote for final passage occur on separate days.

Friday is the last day of the session.

Hundreds of parents and nearly all the legislative Republicans had opposed House Bill 1312, which would have created a standardized form to get an exemption for a child attending public school.

The exemptions, based on religious or personal beliefs, would have remained in place, however.

Rep. Kyle Mullica, D-Northglenn, a nurse, sponsored the bill, which he called a public safety measure in the face of measles cases reported in 22 states, including Colorado.

The bill’s underlying goal was to encourage more people to vaccinate their children, rather than simply notifying their local school that they have opted not to immunize their children.

Opponents deemed it an invasion of privacy and a violation of parental rights by forcing them to register their exemption with the state.

Supporters of the bill expressed their disappointment Thursday.

“House Bill 1312 was a Colorado-specific solution supported by science and evidence,” Stephanie Wasserman, executive director of the Colorado Children’s Immunization Coalition. said in a statement.

“It was a modest bill, the result of tireless effort to address a variety of stakeholder concerns that balanced public health with parental choice. Colorado legislators had an opportunity to help increase the state’s immunization rates. Instead of keeping our children and schools safe, they have chosen to put them at risk.”