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Oregon Immunization Rates

Oregon Immunization Rate Q & A

What do Oregon immunization rates measure?

Oregon immunization rates measure vaccination rates among two-year-olds and adolescents (13- to 17-year-olds) living in a certain geographical area: state, county, or zip code. They tell us how well immunized different areas of the state are based on where people live, not where they seek health care. These are different from what you might know as AFIX (Assessment, Feedback Incentive, eXchange) rates, which measure immunization rates only among individuals who are active patients at a certain clinic.

Who gets included in these rates?

Individuals are included in the rates if they have a post-birth immunization record in ALERT Immunization Information System (IIS) and are Oregon residents based on their most current address.

How are these different from the old Population-Based Rates (PBRs)?

Until 2017, we made adjustments to two-year-old immunization rates to account for potentially missing data based on such factors as the proportion of children born in the county who had a vaccination record in ALERT IIS and the amount of people moving in and out of the county. We have determined that those adjustments are no longer necessary, and now coverage rates are based only on ALERT IIS data.

Why are data adjustments no longer needed?

A very small proportion of vaccination records do not get reported to ALERT IIS. In a 2016 clinical chart review, we found that 97% of clinical records were present in ALERT IIS and adding in those missing records increased vaccination rates by less than one percentage point. ALERT IIS data is highly complete, particularly given recent improvements in electronic health records and data exchange capabilities.

What about completely unvaccinated kids?

It is difficult to say how many unvaccinated kids there are in Oregon. We have no way of knowing if a child is completely unvaccinated since a record may not appear in ALERT IIS. We are confident this is an extremely small proportion of Oregon’s population: just over 2% of kindergartners get an exemption for all school-required vaccines. Within those exemptions, not all kindergartners are completely unvaccinated; they may have received a vaccine prior to claiming an exemption resulting in an ALERT IIS record. OIP’s Population-level immunization rates method accepts a small amount of error and excludes this unknown number of fully unvaccinated kids.

What about kids who moved out of the state?

Unless the new address is reported to ALERT IIS, it is hard to say whether a child has left the state or simply stopped receiving vaccines. We expect that, like unvaccinated kids, the proportion of two-year-olds who have left the state is small. Our assumption is that rates are balanced out by excluding the small numbers of completely unvaccinated kids while also including kids who might have left the state in our data.

My local area’s rates went down based on these new methods. What should I do?

We realize that these new methods will give the appearance of a slightly lowered immunization rate in some counties. Since many Local Health Departments report rates annually to external partners that may be concerned by what appears to be a drop in the number of immunized children we recalculated immunization rates for the past three years so that Local Health Departments and other partners can report these new rates relative to previous years and update tracking measures.

Will Oregon’s Immunization Rates have an impact on local health department required Program Element 43 (PE43)?

PE43 does not include specific immunization improvement metrics. The Oregon Immunization Program requires LHDs to take two actions to improve immunization rates, but hold LHDs accountable for taking the actions, not improving the rates.

Do Oregon Immunization Rates impact Coordinated Care Organizations (CCO) 2-year-old immunization incentive measure?

No. The Coordinated Care Organizations (CCOs) produce their own metrics using a defined patient population.