Hart Van Denburg/CPR News Stephanie Ramirez holds her 15-month-old son Oliver during an appointment for a vaccination at Children's Hospital Colorado.

Update, April 16, 2019: Lawmakers on a House committee advanced a bill to tighten the state's school immunization rules. The bill passed 7-4 along party lines and now goes to the full House. The vote came at 4 a.m. Tuesday morning after a marathon session of testimony. Hundreds turned out to share their views, filling the halls and listening in from overflow rooms.

On a recent visit to the Child Health Clinic at Children’s Hospital Colorado, Stephanie Ramirez holds her 15-month-old son Oliver.

Oliver is wearing a blue t-shirt that says “Mom’s Little Dude.” He’s at the clinic for a shot called Dtap, for diphtheria, tetanus and whooping cough.

“Whhhaaaa!!!” Oliver lets out a wail as a medical assistant administers the shot. But Ramirez said it wasn’t a hard decision to give her “little dude” the immunization.

“It’s safer to me, in my opinion,” Ramirez said. “It just keeps the illnesses away.”

Her doctor, Christina Suh, counsels families about the benefits of getting kids vaccinated, how it protects them from serious diseases and complications.

But not all parents agree with Dr. Suh.

“It is definitely a thing for us, here in our clinic, I’ve been practicing over 10 years and I’ve seen a rise in hesitancy,” Suh said.

State Rep. Kyle Mullica in a January 2019 committee hearing.

Legislator RN

State Rep. Kyle Mullica has seen the same phenomenon.

“I’m the only nurse that serves down here at the Capitol. I’m an emergency room nurse, and I’m also a dad. We just had a baby.” Mullica said.

The Democrat from Northglenn is a father of three. Mullica said he’s seen sick kids in the ER with commonly vaccinated-for diseases like pertussis, or whooping cough.

“It’s completely preventable, and it’s very dangerous,” he said. “I mean kids die from it.”

Those experiences in the ER prompted Mullica to sponsor a bill that would change what parents have to do to enroll unvaccinated children in school.

The bipartisan bill, House Bill 1312, would create a standardized exemption form and require all exemptions to be submitted to the state health department or a local public health agency. Mullica said the first time someone submits a non-medical exemption, it would need to be in person.

“I think that this is a good first step to see if we can solve the problem and really get our immunization rates to a point where we’re not at risk for an outbreak,” he said.

The bill also directs the state health department to include immunization exemption information in an annual presentation to lawmakers, as well as to develop educational material for health agencies and schools. The idea is to target information to areas most vulnerable to an outbreak. That information would give the state board of health authority to determine school-required immunizations based on recommendations from the CDC.

Colorado ranked at the bottom of 49 states in a recent CDC survey for rates of vaccines among kindergarteners for diseases including measles, mumps, chickenpox and whooping cough. About 88 percent of Colorado kids got those shots; the CDC goal is 95 percent.

John Daley/CPR News Pam Long and her son Josh in their Franktown, Colo. home. Long said three doctors told her an abnormal reaction to the vaccine caused her son's brain injury.

The Vaccine Skeptics

But any changes to Colorado’s vaccination opt out is going to be a politically charged and volatile fight, with opponents already organizing against the bill. Pam Long is one Coloradan who is skeptical about vaccines. Five years ago, she fought against a legislative proposal to require additional education before a parent could opt their kid out. It ultimately failed.

“That bill is why myself and a lot of other parents became activists to protect parental rights,” Long said.

Long is the mother of 15-year-old Josh. The two live in Franktown, east of Castle Rock.

Long said Josh got an MMR (measles, mumps and rubella) vaccine when he was 15-months-old. Afterward, Josh developed a slow regression of cognitive skills. Long said three doctors told her an abnormal reaction to the vaccine caused a brain injury.

Today, Josh functions at a first-to-third grade level. It was a turning point in Long’s skepticism of vaccines and the companies making them, she said.

“At that point, we stopped vaccinating both of our children and neither have been vaccinated since then,” Long said.

Long works with the Colorado Health Choice Alliance. The nonprofit's website said the group “believe(s) vaccinations can cause irreparable harm,” and encourages each family to make a choice that’s best for their children.

Long calls Mullica’s bill a slippery slope to making exemptions "difficult and impossible" to get. Opponents are ready to turn out against any changes that could lead to what they view as a more draconian policy, Long said.

"So these measures are just harassment and when they don't work then you see states implement bills like Rep. Mullica originally intended, which was to revoke the exemptions,” Long said.

Hart Van Denburg/CPR News Oliver Ramirez, a 15-month-old, receives a shot during an appointment at Children's Hospital Colorado.

The Lowest Immunization Rates In Colorado

Colorado has so far never made it harder to opt out, though its health department (CDPHE) does post school vaccination rates on an immunization database. The bottom twenty schools have average rates below 57 percent, far lower than the threshold thought to keep a community protected, according to the health department.

The list of the 20 schools with the lowest rates includes a mix of rural, urban, public, private, religious and charter schools. A couple of schools — Crestone Charter School, in Saguache County, and Tara Performing Arts High School in Boulder — recorded immunization rates below 20 percent.

The list includes many smaller schools, as well as five in Boulder County and a couple of home school enrichment programs, which serve homeschooled students.

Among larger schools, those with 100 students or more, there were 20 schools with rates below 68 percent: Mountain Sage Community School in Fort Collins, which has 269 students, documented an average fully vaccinated rate of 36 percent. The largest school on the list, Goal Academy in Pueblo, has 3,765 students and a rate of 66 percent.

The list includes schools along the Front Range in Adams, Boulder, Jefferson and El Paso counties, as well as schools in more rural communities, like Carbondale, Walden, Moffat, Delta and Durango.

Infectious disease experts worry an outbreak could spring up at any time from one of those pockets, which is why they back measures to raise the state’s vaccination rate.

“I think it’s important for Colorado. We’re already seeing vaccine-preventable diseases. They both cost a lot of money and they’re entirely preventable,” said Dr. Sean O’Leary, a pediatrician and pediatric infectious disease specialist at Children’s Hospital Colorado. “Research shows the easier the process for opting out, the higher the exemption rate.”

A recent study found treatment for unvaccinated kids in Colorado resulted in 9,400 hospital and emergency department visits in 2017. It cost $55 million.

Hart Van Denburg/CPR News Oliver Ramirez, a 15-month-old, reacts after getting a shot during an appointment at Children's Hospital Colorado.

Measles Outbreaks

The debate in Colorado comes as the number of measles cases around the country have spiked. The CDC recorded 465 confirmed cases in 19 states including Colorado so far in 2019. The agency said it’s the second greatest number of cases in the U.S. since 2000.

New York has been hit with one of the city’s largest measles outbreaks in decades. It’s caused 285 confirmed cases since last fall. After trying education and outreach, the city declared a public health emergency, requiring unvaccinated people living in Williamsburg, Brooklyn to receive the measles vaccine or face possible fines of $1,000. The outbreak occurred in an Orthodox Jewish community.

According the CDC’s website, the majority of people who got measles were unvaccinated, and the disease can spread when it reaches groups of unvaccinated people.

Measles, which is caused by a virus, was once commonplace, but now can “almost always” be prevented with a vaccine, according to the Mayo Clinic website. It can be serious, even fatal. Due to high immunization rates, measles hasn’t been widespread in the U.S. in more than a decade. But it kills more than 100,000 a year globally, most under age 5.

It’s that concern that’s lead to the push to tighten Colorado’s rules for the second time in the last five years. Hundreds of people are expected for the bill’s first hearing on Wednesday. And on the legislature’s website, the proposal is one of the top three most viewed bills.

Most parents in Colorado do get their kids immunized. But Heather Dragon Graham, a mother in Lafayette, worries about the spread of disease.

"It's real and I've learned that Colorado has quite a few children out there that aren't vaccinated,” Graham said.

Graham says she has thought a lot about vaccines. When her son Myers was two, he was diagnosed with a rare malignant brain tumor. He needed chemotherapy, which weakened his immune system. It was critical other kids in his preschool got vaccinated so Myers wouldn’t get sick while he recovered, Graham said.

“If we're all going to work together as a community and keep our children safe, we should think not only of our kids but other people's kids,” Graham said.