• Original Reporting
  • Sources Cited
Original Reporting This article contains new, firsthand information uncovered by its reporter(s). This includes directly interviewing sources and research / analysis of primary source documents.
Sources Cited As a news piece, this article cites verifiable, third-party sources which have all been thoroughly fact-checked and deemed credible by the Newsroom in accordance with the Civil Constitution.
An adult injects a vaccine into a baby's leg
In this Jan. 29, 2015, photo, pediatrician Charles Goodman vaccinates 1-year-old Cameron Fierro with the measles-mumps-rubella vaccine, or MMR vaccine, at his practice in Northridge, California. (Damian Dovarganes, AP Photo)

Colorado public health officials have worked for years to increase immunization rates for school kids, with a particular concern about the percentage of kindergarteners who are not getting the measles vaccine. 

They’ve offered free shots, sent letters and launched radio ads. Yet, the state’s vaccination rate is dropping.

Statewide, 86.8% of kindergarteners were vaccinated against measles, mumps and rubella last year. That’s the lowest since 2017, erasing any gains the state had made in the prior five years. 

So-called “herd immunity,” the rate of immunization needed to protect unvaccinated people from an outbreak, is 95%. Rates vary widely from school to school, from 100% down to just 20%, creating pockets where Colorado kids are at risk.

As public health officials redouble their efforts, including five new vaccination vans that will travel the state, they’re pointing toward the COVID vaccine controversy and busy post-pandemic schedules as reasons for the drop. 

The number of exemptions filed by parents who did not want their children vaccinated were up, despite a 2020 law that requires them to get a doctor’s signature or watch a 20-minute online video. 

“We’re getting more and more concerned that some of the coverage rates we’re seeing at the district level, even at the county level, and then even statewide for certain age groups are not really where we need to be to confer that herd immunity protection,” said Heather Roth, immunization branch chief at the Colorado Department of Public Health and Environment.

“There’s a larger percentage of our kindergarten kids that fall in this noncompliance area where they don’t have an exemption on file, they’re not up to date, or they have no record on file.”

Measles had been declared eliminated by the Centers for Disease Control and Prevention in 2000 but a handful of outbreaks have occurred in recent years. An outbreak in Ohio last fall and winter sickened 85 children who were not fully vaccinated, including 36 who were hospitalized. Colorado had a measles case in 2019, a Denver adult who had traveled out of the country, as well as two cases in 2016, according to the CDC. 

A few schools in Colorado have measles vaccination rates below 50%, though it’s impossible to know whether rates are actually that low or whether school districts do not have up-to-date records. Colorado law says children cannot attend school without required vaccinations or an exemption on file, but not all school districts adhere to that

Roth said it’s possible that the turbulence surrounding the COVID-19 vaccination caused a drop in other immunizations. But more so, she suspects some parents have been too busy to keep up with their children’s health checkups as they adjust to post-pandemic activities. And some families have no primary care doctor, or they do not have insurance, or are not living in Colorado legally and do not know they can get immunizations for free. 

“Vaccine hesitancy has been around forever, since the very first vaccine was created,” she said. “That’s a piece of it. I think vaccine access continues to be a significant driver. The last few years have been challenging for everyone in a different way.”

Children are required to get not only the measles vaccine but also immunizations against whooping cough, mumps, polio and chicken pox in order to attend a school or child care center in Colorado. Vaccines that aren’t required but are recommended by public health officials are those that protect against meningococcal meningitis, hepatitis A, rotavirus, human papillomavirus, the flu and COVID. 

People line up at Colorado’s mobile vaccine bus to get the Pfizer-BioNTech COVID-19 vaccine at the Snowmass Town Center on Tuesday, Sept. 20, 2022, in Snowmass Village. (David Krause, The Colorado Sun)

Immunization rates were down overall last school year but the biggest drop was among kindergarteners. 

Child care centers had a higher compliance rate than K-12 schools, with 95.7% of babies, toddlers and preschoolers in compliance. That compared with 88.4% of kindergarteners who were in compliance with school immunization rules, the state health department said. It was a 5.2% drop from the prior year.

Free vaccinations available in 570 locations statewide

Colorado now has 570 locations where kids who qualify can get immunizations at no cost. The shots are covered by the federal government and are administered at pediatricians’ offices, public health agencies and school-based health centers. 

State public health officials are also reaching out directly to parents whose children are missing one or more vaccines, hitting them with four rounds of texts and emails. The state health department is running ads this summer urging parents to make sure their kids’ vaccines are up to date. 

And as a new school year begins, five vans will travel the state, offering vaccines as they’re parked outside of schools, community centers and “other places where people feel safe,” Roth said. 


The state health department is also dispatching public health nurses to doctors’ offices in counties where the kindergarten immunization rate is lowest. The goal is to get pediatricians and family medicine physicians to strategize about how to boost rates in their area, Roth said. 

Parents can look up their children’s vaccination records at They can find requirements and exemption rates at specific schools and child care centers at, and they can find out where to get free vaccines at

Jennifer Brown writes about mental health, the child welfare system, the disability community and homelessness for The Colorado Sun. As a former Montana 4-H kid, she also loves writing about agriculture and ranching. Brown previously...

John Ingold is a co-founder of The Colorado Sun and a reporter currently specializing in health care coverage. Born and raised in Colorado Springs, John spent 18 years working at The Denver Post. Prior to that, he held internships at...