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Vaccination Programs: Immunization Information Systems


What the CPSTF Found

About The Systematic Review

The CPSTF finding is based on evidence from a systematic review of 240 studies (108 published studies and 132 conference abstracts; search period January 1994 - April 2011). Included studies represented IIS-supported interventions (e.g., client reminder and recall systems) and described IIS program activities and experiences.

The review was conducted on behalf of the CPSTF by a team of specialists in systematic review methods, and in research, practice, and policy related to increasing appropriate vaccination.


Immunization information systems now operate in all U.S. states. Most IIS serve all children, adolescents, and adults in the jurisdiction (CDC External Web Site Icon).

Minimum functional standards External Web Site Icon for the operation of immunization information systems were developed in the United States in 1997 by the Centers for Disease Control and Prevention, the National Vaccination Advisory Committee, and immunization program grantees. In 2012, CDC and the IIS community updated the IIS Functional Standards to be implemented from 2013-2017.

Summary of Results

More details about study results are available in the CPSTF Finding and Rationale Statement pdf icon [PDF - 168 KB].

The systematic review included 240 studies.

Studies were assigned to nine categories.

  • Overall evidence on effectiveness
    • A published study from Australia reported an increase in vaccination rates following adoption of a national IIS. This change, however, was likely due to an increase in participation rates associated with incentive payments offered to families and vaccination providers.
    • A cross-sectional study from the United States reported that medical practices using IIS did not have significantly higher vaccination rates than did practices not using IIS.
  • IIS-supported interventions to increase vaccination rates
    • Client reminder and recall systems
      • Vaccination rates: median increase of 6 percentage points (13 studies with 16 study arms)
      • Additional descriptive studies reported client reminder and recall activities (17 studies).
    • Provider assessment and feedback
      • Vaccination rates: median increase of 9 percentage points (5 studies)
      • Additional descriptive studies reported the use of IIS to support the conduct of these interventions (10 studies).
    • Provider reminders (also referred to as clinical decision support for immunizations, or CDSi)
      • Vaccination rates: increase of 14 percentage points (1 study)
      • Many IIS in the United States have built-in reminders that prompt vaccination providers when a client record is consulted.
  • IIS use in vaccination-related decisions by clinicians, schools, and health care systems
    • No studies evaluated the use of IIS by vaccination providers at the clinic level.
    • Studies described use of IIS in school settings (10 studies).
    • Studies described use of a state IIS by a health care system (4 studies). Of these studies, three described using IIS data for quality measurements, including HEDIS (Healthcare Effectiveness Data and Information Set).
  • IIS use in public health response
    • Studies described use of IIS to respond to outbreaks of vaccine-preventable disease (18 studies), including
      • Targeted recalls of unvaccinated patients
      • Retrospective review of vaccine uptake to monitor provider adoption of revised vaccination recommendations
      • Guiding decisions around 2009 H1N1 influenza vaccine distribution and client management
    • Studies described use of IIS to respond to a public health emergency situation (3 studies). Of these, two detailed the use of IIS to avoid administering unneeded vaccines to people displaced by Hurricane Katrina.
  • IIS to support vaccine management
    • Studies described the use of IIS in the process of vaccine supply management, distribution, and accountability (14 studies). Of these, 10 involved doses distributed as part of the U.S. Vaccines for Children Program External Web Site Icon.
  • IIS to assess vaccine safety and effectiveness
    • Studies described use of IIS in assessment of, or response to, vaccine safety issues or in evaluation of vaccine effectiveness (17 studies).
  • IIS as a tool for public health decision support
    • Included studies described a range of IIS surveillance capabilities
      • Coverage assessments for specific vaccines (51 studies)
      • Investigations of vaccination rates among high risk subsets of the population (32 studies)
      • Ability to monitor uptake of new vaccines (16 studies)
  • IIS integrated with other child health information systems
    • Studies discussed integration of additional child health data (e.g. blood-lead levels, early hearing detection) into existing IIS (8 studies).
  • IIS contributing to change in documentation
    • Studies compared the completeness of individual IIS vaccination records with some other immunization data source (e.g. medical records, parental report; 24 studies).

Summary of Economic Evidence

More details about study results are available in the CPSTF Finding and Rationale Statement pdf icon [PDF - 168 KB].

The economic review is based on evidence from 14 studies (12 published papers and 2 government reports; search period January 1994 – March 2012).

  • Included studies evaluated the cost of IIS (9 studies; 7 assessed system costs, and 2 assessed the cost of exchanging immunization data), benefits of IIS (9 studies), and cost-benefit ratios (4 studies).
  • Program costs
    • Estimated total costs ranged from $205,077 to $108 million.
    • Estimated annual cost per child ranged from $5.40 to $60.82.
    • Estimated cost per vaccination record ranged from $0.11 to $12.88.
  • Benefits evaluated in the included studies were mostly specific to savings associated with administrative efficiency and decreased over-vaccination.
  • Cost-Benefit
    • One study modeled cost and benefits of a nationwide IIS and indicated a benefit-cost ratio of 3.5:1, meaning $3.50 in savings for every dollar invested.
    • A state-level study modeled anticipated yearly benefits and found that compared with annual IIS costs to the state, the benefit-cost ratio was 1.59:1.
    • At the city level, one evaluation based on a single year found that using an IIS compared with manually performing immunization activities resulted in net savings of $36,815.
    • Among health care systems, a managed care organization estimated a return of $8 for every $1 spent after linking to a state IIS for electronic data reporting versus manually retrieving claims data.
  • All studies provided information about IIS implemented in the United States and focused on pediatric immunizations.
  • Variability in costs might be attributable to the scale of the IIS and the target population size.
  • Of the seven studies that assessed system costs, six evaluated systems implemented from 1997 to 2002. Cost and benefit data from these studies may be less applicable today owing to changes in system technology, data exchange methods, availability of vendor support, and system functionalities.


Results of this review are broadly applicable to IIS implemented in the United States for use with the childhood vaccination series. This is especially true as systems achieve levels of provider and client participation demonstrated by Sentinel Site programs External Web Site Icon.

Evidence Gaps

CPSTF identified several areas that have limited information. Additional research and evaluation could help answer the following questions and fill remaining gaps in the evidence base. (What are evidence gaps?)

  • What is the overall impact of IIS (or IIS activities) on vaccination rates in the general U.S. population or among target populations that have gaps in coverage?
  • How useful is IIS for vaccination providers in clinical settings?
  • How do participation rates and records capture vary based on demographic characteristics, such as race and ethnicity, household income, and insurance status?
  • What is the frequency and reach of various IIS activities within the population?
  • What are the costs of implementing present-day IIS, either with systems developed in-house or with systems supported by vendors?
  • What are the economic returns associated with additional benefits (improved efficiencies and decreased time associated with conducting provider reminder/recall functions, provider assessment and feedback efforts, improved vaccine supply and management, and reduced morbidity and mortality)?
  • What is the cost to connect between providers’ Electronic Health Records (EHRs) and central IIS?

Study Characteristics

  • Studies evaluated systems in the United States (209 studies), Australia (2 studies), and other countries (5 studies).
    • Of the studies conducted in the United States (52% of the included studies), 108 described actions and capabilities of systems within the IIS Sentinel Site program External Web Site Icon.
    • Most U.S. studies considered children and vaccinations within the childhood series. Only 33 studies (20% of the included studies) that reported vaccination outcomes described the use of IIS for adolescents and 12 (7%) described the use of IIS for adult populations, with most studies focused on influenza vaccination.

Of the included studies, 47 evaluated or described one or more of the following interventions supported directly by an IIS or population-based vaccination database:

  • Client reminder and recall notices
  • Provider assessment and feedback activities
  • Provider reminder systems

Studies evaluated IIS used in various settings for different reasons:

  • U.S. studies evaluated or described use of IIS by vaccination providers, schools and day cares, or health care systems (14 studies).
  • U.S. studies described IIS interactions with schools and day cares (10 studies).
  • U.S. studies evaluated or described use of IIS in responses to outbreaks of vaccine-preventable disease or other public health emergencies (18 studies).
  • Studies described use of a state IIS by a health care system (4 studies).
  • Studies described IIS use to facilitate vaccine ordering, inventory monitoring, and vaccine-related accountability (14 studies).
  • Studies (12 from the U.S.) described IIS use to assess or respond to vaccine safety issues or to evaluate vaccine effectiveness (17 studies).