By Sarah Glen and Ann Schimke, Chalkbeat 

This week, we published a database of school-by-school immunization rates for Colorado’s 30 largest school districts. Chalkbeat staff have combed through the data looking for trends and trouble spots. Here’s what we’ve found so far.

Note: We excluded certain non-typical schools from these charts, including home school enrichment programs, night school programs and independent living programs for special education students.

Most of the highest exemption schools are in the Boulder Valley district

Among the 15 schools with the highest rates of students exempt from vaccinations, more than half are in the Boulder Valley School District. Two of those schools — Jamestown and Gold Hill elementaries — are tiny, enrolling 26 or fewer students.

10 districts with the most highly immunized schools

These districts have the greatest proportion of schools where at least 90 percent of students are fully immunized. Four of these districts — Cherry Creek, Adams 12, Poudre and Colorado Springs 11 — are among Colorado’s 10 largest. Cherry Creek is one of the few districts in Colorado that has a nurse in every school.

10 schools with the biggest compliance rate increases

After posting lackluster compliance rates last year, these 10 schools have all made substantial improvements in making sure they have students’ immunization and exemption paperwork. (Check out last year’s immunization database here.)

10 schools with the biggest compliance rate decreases

The reason so many high schools are on this list is likely because of a new rule in 2015-16 that required high-schoolers to have two doses of the chickenpox vaccine. As a result, students who previously would have been considered fully immunized, became non-compliant.

10 schools with the biggest exemption rate increases

These schools — all with exemption rate increases of 12 percentage points or more — represent a mix of districts and traditional or charter status. Most are high schools or schools with ninth-12th grade.

10 schools with the biggest exemption rate decreases

These schools are mostly secondary schools in a variety of districts. Two of the schools — Jamestown and Gold Hill elementaries in Boulder Valley — are extremely small, meaning that changes for just a couple students can create a sizable swing in the school’s rates.

Chalkbeat is a nonprofit news site covering educational change in public schools.