Research and Evaluation

• Oregon County Rates 
• National Immunization Survey Rates 
• AFIX 
• Vaccine Adverse Event Reporting System (VAERS) 
• 2004-05 Flu Season Evaluation 
• Oregon School Exemption Study 
• 1999 Survey of Two-Year-Olds 

Making Heads and Tails of Immunization Measures
We use immunizations as a building block for preventive care, yet how do we measure our success or identify challenges? Three good methods are available for measuring rates in Oregon, with respective roles and caveats: Oregon countywide population-based rates from ALERT; national population-based survey rates from the National Immunization Survey (NIS); and Oregon clinic-specific rates from ALERT.

ALERT registry data provide a great starting point for assessing population-based rates in Oregon because the registry is so well populated; over 85% of immunization providers in Oregon are reporting some data to ALERT. However challenges to producing accurate coverage rates based on incomplete registry data include the effect of early child mobility (children moving into and out of the state and county) and incomplete or non-existent reporting to the ALERT registry by some Oregon providers and hospitals. The Immunization Program developed a methodology using standard demographic tools, ALERT registry data, and mobility data, to determine countywide rates for two-year-olds. These estimates allow for comparisons among counties because the entire population is assessed so the numbers are strong, and adjustments have been made for biases due to poor reporting or movement of children.

The NIS is a phone survey of families of young children and their healthcare providers, collecting immunization data to determine coverage rates nationwide. The NIS is a useful tool to monitor immunization trends over time for each state, and to detect changes in coverage levels among states. The NIS surveys approximately 200-400 families, which allows for state-to-state comparisons and state trending over time, however it does not allow for any estimates of sub-populations in Oregon, such as county rates.

• Oregon's 4:3:1:3:3:1 Immunization Trends for Two-Year-Olds 
  
• Oregon's NIS Up-to-Date Rates - 2008
  Table                 Graph
  
• NIS FAQs 2006
  
• NIS Press Release August 2006
  
• NIS website (Clicking here leaves this site)

In Oregon, the Immunization Program uses ALERT data to measure rates for children served at a specific clinic. This clinic assessment provides immunization rates and other related measures that help a clinic evaluate their practices and track improvements over time. It is a quality improvement tool for clinics interested in using data to improve practice. Click here  for more information on AFIX.

Before vaccines are licensed, the Food and Drug Administration (FDA) requires manufacturers to conduct extensive safety testing. Although careful studies are done before a vaccine is licensed, some rare side effects, or “adverse events,” may not be detected. After a vaccine is licensed, the FDA and the Centers for Disease Control and Prevention (CDC) monitor vaccine safety through the Vaccine Adverse Event Reporting System (VAERS). VAERS is a passive surveillance system that receives reports from healthcare providers, patients, parents, and others on adverse events occurring after vaccination.

However, not all events reported to VAERS are caused by the vaccine. Thus, VAERS data should be interpreted with caution. Some adverse events occurring after vaccination are attributed to a previous underlying condition or illness, other medications, or mere coincidence. If a case looks as though a vaccine might have caused an adverse event, the CDC will investigate it further.

In 2008, VAERS data was release to the public for the first time, allowing the Oregon Immunization Program to monitor Oregon VAERS reports.

• 2008 Oregon VAERS Summary 

More information on VAERS can be found on the CDC website.

• School Exemption Study 

Giving it Our Best Shot:
An Evaluation of the Oregon Department of Human Services' Response to the 2004 - 2005 Flu Vaccine Shortage

Executive Summary

Background on the 2004-05 flu vaccine shortage, chronicle of events and lessons

learned from the flu season.

Full Report (PDF) (1.8M)

1999 Oregon Immunization Survey of Two-Year-Olds

In 1996, Oregon surveyed parents of two-year-olds to determine immunization rates and to identify barriers to immunization faced by those under-immunized. This information was used to develop recommendations for improving immunization services in Oregon. The Executive Summary presents the basic study, results and recommendations. The entire report is available in PDF format for downloading.


For additional information on this study, please contact:
Immunization Program
Public Health Division

Department of Human Services
(971) 673-0300