Maricopa County Department of Public Health confirmed three related cases of measles. One case is an adult and the other two are kids. Whether these cases transition from an outbreak to an epidemic will depend on how many contacts the cases had with unvaccinated classmates.

MCDPH teams will also be checking the vaccination status of the classmates of the pediatric cases. Vaccination rates at the school attended by the index cases will be a key determinant of whether these initial cases cascade into an epidemic. The downward slide of vaccination rates makes it more likely that we’ll have additional cases coming from the index case school. But why?

As has been the case throughout the Ducey Administration, childhood vaccination rates have continued their insidious decline, with the statewide immunization rate for Kindergarteners now at 91%… well below the community immunity threshold for measles of 95%.

See: Governor: Education parental choice on value of vaccinations by Howard Fischer

State law requires the ADHS to collect data about the vaccination rates for Child Care/Preschool; Kindergarten; and 6th grade. Schools submit the data to the ADHS each fall. In the spring ADHS is required to publish the data by school. Rather than showing the actual vaccination rates, the system records the percentage of exemptions (personal, medical and religious) as a proxy for vaccination rates.

ADHS posted the data in April. There are some aggregate tables but also a big giant spreadsheet with the vaccination rate by school. A clever parent that knows how to sort in Excel could quickly find the vaccination rate for their kid’s school. Here’s the big file with all the school data: Arizona Reporting Schools Coverage

There are also some summary tables with coverage levels for various vaccines by geographic region:

Vaccination rates aren’t uniform across the state. Yuma and Santa Cruz counties continue to enjoy the highest vaccination rates (above 95% for MMR among Kindergarteners). Also as usual… Yavapai had the lowest vaccination rates with MMR coverage at only 74% and nearly 10% of students totally unvaccinated among Kindergarteners.

Another continuing trend… students enrolled in charter schools have vaccination rates much lower than students in district public schools. Also, higher income districts tend to have lower vaccination rates.

There are several evidence-based strategies that can be implemented at a statewide level, but such initiatives require leadership by a state health department director & governor…  something that’s in short supply these days.

Interventions to increase pediatric vaccine uptake: An overview of recent findings

For information on school immunization requirements, review the Guides to Arizona Immunization Requirements for Child Care/Preschool and Grades K-12.

Far and away the most effective (and highest ROI) intervention to improve childhood vaccination rates is to eliminate the ability for parents to exempt their kid from the school vaccine requirement with the ‘personal exemption’. Governor Ducey & the state health directors during his tenure have had zero interest in eliminating the personal exemption.

Editorial Note: Governor Ducey has been hostile to vaccination mandates (e.g., eliminating the personal exemption), even signing several bills eroding public health authority (see PowerPoint). His health directors remained completely silent as he signed those bills – signaling their tacit support for the erosion of public health authority. 


Perhaps childhood vaccination will again become a priority when we get a new governor in 118 days (but who’s counting).