Colorado Gov. Jared Polis signed a highly contested vaccine bill Friday afternoon with no fanfare or advance public notice.

Senate Bill 163, which adds a step for parents who want to exempt their children from vaccines for nonmedical reasons, received final legislative approval in the last days of the session. It’s aimed at increasing Colorado’s lowest-in-the-nation child vaccination rates.

“I think it’s good that we’re dealing with facts and that we’re dealing in science,” said sponsor Rep. Kyle Mullica, a Northglenn Democrat and emergency room nurse.

The new law requires parents who choose not to vaccinate their kids for nonmedical reasons to either provide an exemption form signed by a medical professional or take an online module about vaccines and submit a completion certificate. Schools will also have to provide students and parents with their vaccination and exemption rates. Children who are home-schooled are exempt.

The Department of Public Health and Environment has until Jan. 1 to provide a standardized exemption form. Schools have to report their rates annually for the measles, mumps and rubella vaccines by Feb. 15. The state will keep the information in its immunization tracking system.

Polis gave his support for the bill after opposing a similar bill last year.

Republicans — except Senate sponsor Kevin Priola of Henderson — voted against the bill, saying it violates parents’ rights and creates privacy issues. Legislative support for the bill was not in question given that Democrats controlled both chambers of the General Assembly, but hundreds of parents rallied against the bill, making it more difficult to pass after the coronavirus pandemic shortened lawmakers’ session.

A majority of Coloradans have indicated their support of tightening exemptions, according to polling by Keating Research.