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Immunization Information System Progress --- United States, 2004

One of the national health objectives for 2010 is to increase to at least 95% the proportion of children aged <6 years who participate* in fully operational, population-based immunization registries (objective no. 14-26) (1). Immunization registries are confidential, computerized information systems that collect and consolidate vaccination data from multiple health-care providers, generate reminder and recall notifications, and assess vaccination coverage within a defined geographic area (2,3). A registry with added capabilities, such as vaccine management, adverse event reporting, lifespan vaccination histories, and linkages with electronic data sources, is called an immunization information system (IIS). This report summarizes data from CDC's 2004 IIS Annual Report, a survey of 56 grantees in 50 states, five cities, and the District of Columbia (DC) that receive funding under section 317b of the Public Health Service Act. The findings indicate that approximately 48% of U.S. children aged <6 years participated in an IIS. Moreover, 76% of public vaccination provider sites and 39% of private vaccination provider sites submitted immunization data to an IIS during the last 6 months of 2004. Overcoming challenges and barriers to increasing the number of provider sites and the percentage of children aged <6 years participating in an IIS is critical to achieving the national health objective. CDC has developed a plan of action to address those challenges. Major components of the plan include, but are not limited to, a multiyear IIS business plan for each grantee and enhanced technical assistance to grantees with unresolved challenges.

The 2004 IIS Annual Report, a self-administered, Internet-based questionnaire, was made available to immunization program managers as part of an annual reporting requirement. As in previous years, respondents were asked about the number of children aged <6 years participating in the IIS, the number of health-care provider sites participating in the IIS, and the ability to perform other programmatic and technical functions (e.g., data linkages with other public health programs, data use, vaccine management, software/hardware capability, and reporting functions). All 56 grantees were asked to complete the questionnaire; 51 reported on the number of children aged <6 years participating in an IIS. Estimates of the total number of children aged <6 years were based on 2004 U.S. Census data.

The findings suggested that, of approximately 23 million U.S. children aged <6 years, an estimated 48% (11 million) participated in an IIS. Ten (18%) grantees (Alabama, Arizona, Delaware, Michigan, New Mexico, New York City, North Dakota, Oregon, Philadelphia, and Wisconsin) have achieved the national health objective of >95% of children aged <6 years participating in an IIS (Figure). An additional seven (13%) IIS grantees (Arkansas, Mississippi, Montana, Oklahoma, Missouri, Rhode Island, and Tennessee) were approaching the national health objective, with participation rates of 81%--94%.

Approximately 76% of public vaccination provider sites and 39% of private vaccination provider sites submitted vaccination data to an IIS during the last 6 months of 2004. Twenty-eight (50%) grantees reported that >95% of public provider vaccination sites submitted vaccination data to an IIS; five (9%) reported submission of vaccination data by 81%--94% of public provider vaccination sites. Seven (13%) grantees (Arkansas, Connecticut, Mississippi, New Mexico, Philadelphia, San Antonio, and South Dakota) reported that >95% of private provider vaccination sites submitted vaccination data to an IIS; eight (14%) (Arizona, Delaware, DC, Michigan, North Dakota, Oregon, South Carolina, and Wisconsin) reported data submission by 81%--94% of private provider vaccination sites.

Reported by: G Urquhart, J Kelly, B Rasulnia, Immunization Svcs Div, National Immunization Program, CDC.

Editorial Note:

In 2004, approximately 48% of U.S. children aged <6 years participated in an IIS; the national health objective for 2010 is to increase this proportion to at least 95%. The 2004 rate represents a 4% increase from 2003, with approximately 1 million more children participating in an IIS (4). In addition, private health-care--provider site participation in an IIS increased by 3%. These small percentage increases from 2003 indicate that several grantees must overcome substantial obstacles to meet the national health objective, some of which have been reported previously by the National Vaccine Advisory Committee (2) and CDC (5). These include inadequate technical and managerial resources to oversee IIS development and implementation or provider perceptions about the administrative burden on staff. To address some of these problems, CDC developed a plan of action that includes grantee development of IIS business plans and enhanced technical assistance to select grantees.

A detailed IIS business plan is a requirement in the 2006 annual grantee application for those grantees requesting IIS funds exceeding $100,000. An IIS business plan summarizes the operational and financial objectives of an immunization program and details activities and budgets, indicating how objectives should be achieved. Enhancing business best practices and project management methodologies should assist grantees in planning, developing, and implementing IIS activities throughout the project lifecycle. Use of this plan creates a transparent structure for operational and financial accountability for both grantees and CDC. This methodology will provide a common understanding of the programmatic and technical challenges faced by grantees in IIS planning, development, implementation, maintenance, and evaluation.

In addition, a grantee business plan will assist CDC in monitoring IIS project activities more closely for those grantees that require additional technical assistance. To identify technical assistance needs, immunization program grantees were stratified into three groups on the basis of 2004 IIS Annual Report data and input from CDC IIS staff. The first group of grantees reported no or very low child participation rates and was identified for "active IIS project intervention." This group represents approximately 38% of all U.S. children aged <6 years and is considered to be a primary target group for enhanced technical assistance. The second group includes grantees that have a plan to address their challenges and are making satisfactory progress. These grantees are identified as "under active IIS project implementation" and represent approximately 25% of U.S. children aged <6 years. The third group consists of grantees identified as "mature IIS projects or making excellent progress" and represents approximately 37% of U.S. children aged <6 years. Interventions must be targeted to the first group if IIS grantees are to meet the 2010 national health objective.

To target interventions to the first group for the coming year, CDC has identified grantees amenable to technical or administrative support. CDC will provide enhanced technical support for these grantees. Enhanced technical support services might include but are not limited to the following: assessment of grantee accomplishments and barriers, assistance in the development or refinement of a business plan or reporting requirements, and proposed plans to remediate barriers and challenges. Key performance indicators will be designated to evaluate the success of grantee interventions.

The findings in this report are subject to at least two limitations. First, data from the 2004 IIS Annual Report are self-reported and might result in reporting bias. Second, because some grantees did not report data, the participation of children aged <6 years and provider participation rates might be underestimated.

Implementing CDC's plan of action will enhance IIS function and use. As a result, IIS likely will be 1) more comprehensive in geographic area participation and coverage levels; 2) interoperable with other public health and clinical information systems; and 3) able to generate data to support all aspects of immunization program operations at national, state, and local levels.


  1. US Department of Health and Human Services. Healthy people 2010, 2nd ed. With understanding and improving health and objectives for improving health (2 vols.). Washington, DC: US Department of Health and Human Services; 2000.
  2. National Vaccine Advisory Committee. Development of community and state-based immunization registries: report of the National Vaccine Advisory Committee (NVAC). Atlanta, GA: US Department of Health and Human Services, CDC; 1999. Available at
  3. Linkins RW. Immunization registries: progress and challenges in reaching the 2010 national objective. J Public Health Management Practice 2001;7:67--74.
  4. CDC. Immunization information system progress---United States, 2003. MMWR 2005;54:722--4.
  5. CDC. Immunization registry strategic plan, 2002--2007. Atlanta, GA: US Department of Health and Human Services, CDC; 2002. Available at

* Participation is defined as a child having two or more vaccinations recorded in an immunization information system.

Number of provider vaccination sites (public and private) is based on grantee self-reports.


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Date last reviewed: 11/17/2005


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