Monitoring vaccination coverage rates is important to the people of North Dakota, to public and private health-care providers and to government agencies. Maintaining high vaccination coverage helps protect all North Dakotans from vaccine preventable diseases. With timely, detailed immunization data the ability of all stakeholders to coordinate effective vaccination strategies and help maintain high vaccine coverage rates is greatly increased. There are a variety of methods and surveys to measure vaccine coverage in North Dakota.
North Dakota Immunization Information System (NDIIS):
A widely used accepted source for immunization data is immunization information systems (IIS). The North Dakota Immunization Information System (NDIIS) is a secure, population-based system that consolidates immunization information for healthcare providers, public health, and North Dakotans. This immunization information is critical to guide patient care, reduce healthcare costs, improve immunization rates and reduce vaccine-preventable diseases. IIS data is a reliable data source for assessing vaccination coverage at the state, county, and local level and provides more comprehensive data than other sources are able to provide. However, IIS data also has limitations. First, an IIS is only as good as the data entered in the system. The North Dakota IIS, has high participation from immunization providers but not all immunizations, specifically for adults, may be entered in the IIS. Second, the population of North Dakota residents in the IIS is used as the denominator for coverage rates, however the NDIIS must rely on outside sources to identify people who have moved out of state or who have moved in and out of different areas within the state. As a result, the NDIIS may have more people counted in the denominator than actually live in the area which can lead to an underestimation of vaccination coverage compared to other sources like the National Immunization Survey (NIS).
School Immunization Coverage Rates
The DHHS Immunization Unit collects vaccination data for North Dakota K-12 schools annually. Immunization coverage rates by school year, grade, and school can be viewed on the School Immunization Coverage Rate dashboard.
National Immunization Surveys (NIS):
The NIS are annual telephone surveys that provide current, population-based, estimates of vaccination coverage among children and teens. There are also limitations of NIS data. First, it takes a year to collect the target sample size per area and, as a result, NIS data are reported for the previous year leaving a gap between changes in the vaccine schedule and evaluation by the NIS. Second, the NIS is not designed to provide precise estimates for smaller geographic areas or for population subgroups within states.
Behavioral Risk Factor Surveillance System (BRFSS):
The BRFSS is the world’s largest ongoing telephone health survey system, tracking health conditions and risk behavior in the US annually since 1984. For determining influenza vaccine coverage the BRFSS is one of the best methods. It has limitations in that it requires survey respondents to self-report vaccination coverage unlike the NIS that verifies immunization data with provider records.