Modernizing Immunization Information Systems

This issue brief outlines key priorities and considerations for modernizing Immunization Information Systems, including leveraging federal funding available to support these efforts.


Governors are responsible for making strategic decisions on how best to spend limited public health resources during the COVID-19 pandemic. Governors have the opportunity to leverage federal funding from the American Rescue Plan Act (ARPA) and other COVID supplemental funds to both improve current response efforts and make lasting investments in public health infrastructure. Modernizing public health data systems, improving surveillance and analytic capabilities, and improving real-time sharing between public health and health system partners can help state leaders respond to the current crisis while better preparing states to prevent and respond to outbreaks of infectious disease in the future.

The COVID-19 pandemic revealed a number of challenges for public health information systems, including the limited capacity of some existing state Immunization Information Systems (IISs, also commonly referred to as immunization registries) to dramatically scale up during the COVID-19 vaccination effort. Many state systems struggled to accommodate additional demand, implement new functionalities, onboard immunization providers, support interoperable exchange with health care partners and enable timely reporting of immunization data to federal partners.

A modernized, interoperable immunization data infrastructure, capable of securely exchanging data in real time with health system and federal partners, is critical to the current COVID-19 response. It can also assist efforts to promote “catch up” vaccinations for routine childhood and seasonal immunizations that have lagged during the pandemic, as well as efforts to limit the spread of future infectious diseases. Further enhancements to IIS capabilities and functionality can also promote consumer access to vaccination records, facilitate state-to-state information sharing, improve analytic capabilities to better target vaccine resources and support vaccine program activities that can better prepare states for booster shots or future pandemics. As states provide third vaccine doses to immunocompromised individuals and prepare for potential booster efforts for the general public, further enhancements to IIS capabilities and functionality can support state leaders by enabling improved consumer access to vaccination records, facilitating state-to-state information sharing, improving analytic capabilities to target vaccine resources and supporting vaccine program activities.

This issue brief provides Governors and senior state officials with key priorities and considerations for modernizing IISs, including leveraging federal funding available to support these efforts. Specifically, this issue brief outlines key functions and current challenges for IISs, available federal funding streams that can support IIS modernization and potential policy, programmatic and technology changes state leaders may consider to strengthen and improve their immunization data infrastructure.


IISs are confidential, population-level databases operating across all 50 states, territories and several large metropolitan areas that record all immunization doses administered by participating providers in a jurisdiction. In most jurisdictions, IISs have been operational for decades and provide services to public health officials, clinicians and other immunization stakeholders such as enabling access to consolidated individual immunization histories, community and population-level coverage rates to support disease surveillance and outbreak activities and other programmatic assistance like vaccine ordering and management as well as reminders to ensure on-time vaccinations. While the Centers for Disease Control and Prevention (CDC) maintains a set of functional standards for IISs, these systems are governed and maintained at the state and local levels, with some variation in function, capacity, data quality and regulations around sharing immunization information both within and outside of jurisdictions.

Table 1 illustrates the variety in IIS capabilities across jurisdictions prior to the COVID-19 pandemic. Due to limited resources, states have prioritized different functional standards according to their program needs, and many IISs have not achieved functional standardization. This has limited the ability of some IISs to efficiently respond to increases in demand during the COVID-19 vaccination effort.

Table 1: IIS Activities as of February 2020

ActivityPercent of Responding IIS Programs with Activity
Support patient look-up and vaccine tracking for mass vaccination86.8
Use IIS to conduct emergency preparedness activities77.4
Have decision-making authority over IIS functions66
Provide Healthcare Effectiveness Data and Information Set (HEDIS) reports to health plans64.2
Exchange data with Medicaid programs45.3
Assess coverage by geographic region41.5
Conduct centralized reminder/recall37.7
Give public access to IIS portal30.2
Exchange data with other states or regions20.8

Source: 2019 AIM Annual Survey. The survey was administered from October 2019–February 2020 and 53 (83 percent) immunization programs responded

With an estimated 10-fold increase in submissions and queries to IISs during the COVID-19 pandemic, need for investments in capacity and the ability to exchange information with federal and health care partners were highlighted by the public health emergency. Many states made initial improvements to their IISs during the pandemic. However, many states still have legacy systems that are laborious to maintain and may struggle to meet additional demands from the continued COVID-19 vaccination effort. IISs have also struggled with data quality and the volume of bi-directional queries with provider electronic health record (EHR) systems, contributing to reporting challenges during COVID-19 and impeding the timely exchange of information with health care providers.


A variety of existing and COVID supplemental federal funding sources are available for states to support vaccination activities, which may include expanding and strengthening IIS infrastructure (see Appendix A for a description of these funding streams). For example, supplemental Electronic Laboratory Capacity (ELC) funding is available for state departments of health to strengthen a range of COVID-19 testing and epidemiologic surveillance. The Coronavirus Response and Relief Supplemental Appropriations Act of 2021 (P.L. 116-260) provides support to state immunization programs to improve and leverage IISs to support efficient COVID-19 vaccination.

Guidance to state immunization programs from the CDC provides additional activities that states may consider for improving and modernizing IISs systems using these funds, including:

  • Promoting and implementing email and text messaging reminder/recall activities;
    Monitoring and managing the COVID-19 vaccine supply to ensure the vaccine is broadly available and resources are deployed to underserved areas;
  • Developing health information infrastructure and IIS upgrades to improve data quality and ensure robust reporting;
    Ensuring timely and accurate reporting of vaccine administration, demographic and other data to local health entities and other partners;
  • Providing consumer access to immunization records including methods to securely document COVID-19 vaccination using a “digital vaccination card;” and
  • Other improvements such as upgrading IIS to the latest version of the platform, supporting data exchange, enhancing IIS analytics and visualization capabilities, and moving to the cloud.


Technical resources specific to IIS upgrades exist for state immunization programs. The CDC laid out strategic priorities for IISs in its IIS Strategic Plan and maintains a set of Core Functional Standards, which set out operational, data quality and technology needs. Additionally, the Public Health Informatics Institute (PHII) developed an IIS Functional Model framework that outlines core IIS functions and capabilities in collaboration with the CDC, the Public Health Informatics Institute and immunization jurisdictions. Core functions include the ability to support interoperability, forecast necessary doses, ensure data quality, provide public data access, manage participating organizations and facilities, manage patient immunization records and manage vaccine inventory.

As Governors and senior state leaders continue to make strategic decisions for strengthening public health infrastructure, they might consider the following policy, programmatic and technology changes to support vaccination efforts and preparedness against future outbreaks.

1) Strengthen and augment IIS technical capacity

Many states have either moved to cloud-based systems or developed parallel infrastructure, such as data lakes, that can augment existing IIS capacity and enable them to regularly communicate with authorized providers, health plans and health information exchanges (HIEs) about vaccination rates within patient populations.*

2) Invest in immunization workforce and provider capacity

An ample and well-trained IIS workforce is critical to maintaining high-performing IISs. In some cases, limited resources have contributed to difficulties with recruiting and maintaining highly trained individuals. Improving the quality of immunization data is at the center of many states’ efforts to enhance equity in vaccine distribution and uptake. States can improve analytic expertise and capabilities to support public-facing dashboards and provide direction to programmatic efforts by blending and braiding various funding streams to prioritize a strong data workforce and analytic capabilities. Several states are also using federal funding to support provider enrollment and training on IISs.

3) Improve Standardization and Interoperability

The CDC’s IIS functional standards provide detailed descriptions of the “operations, data quality and technology needed to support immunization programs, vaccination providers and other immunization stakeholders with their immunization goals.” The American Immunization Registry Association further supports immunization programs by testing and measuring the capacity of each IIS to meet standards through their Measurement and Improvement Initiative. By prioritizing and calling on immunization programs to meet these functional standards, Governors can address challenges that have hindered interoperability to date.

4) Support data quality improvement

Ensuring the completeness and quality of immunization data, particularly race and ethnicity data for administered vaccines, has presented an ongoing challenge for state leaders. States have adopted policy and programmatic strategies to improve these data, including incentives for providers and partnerships with HIEs or EHR consortiums to gather more complete race and ethnicity data, as well as standardizing data collection. In general, states have differing provider requirements to report vaccines administered into the IIS or whether participation in IISs is “opt in” or “opt out,” which can affect the completeness of data within the system. Requirements may also be different for children and adults. States may assess IIS authorizing legislation or regulatory frameworks for opportunities to improve completeness and accuracy. Lastly, many IISs lack the capacity to address duplicate entries or amend incorrect information. Working with vendors to identify technical fixes, such as bulk patient matching, may be low hanging fruit for improving IIS data quality.

5) Facilitate Cross-Jurisdictional Data-Sharing

The ability of IISs to seamlessly share vaccination data across jurisdictions can improve visibility into vaccination rates and improve patient care for individuals who may move or travel between states. The CDC’s Immunization Gateway (IZ Gateway) supports the exchange of immunization data between participating IISs, provider organizations and consumer applications. While the IZ Gateway has multiple components, its Share program allows information exchange across participating IIS jurisdictions. State leaders may assess whether connecting to the IZ Gateway Share component is permissible under current state regulations and consider facilitating policy changes and data use agreements to share IIS data across state lines, especially with neighboring states.

6) Support Consumer Access to Individual Immunization History

Enabling consumer access to vaccination histories has been a longstanding function of IISs. A number of colleges, universities and employers have announced plans to require proof of COVID-19 vaccination, making the ability of individuals to access digital immunization records especially important. Accordingly, many states are moving to facilitate consumer access to vaccination records through their IISs, with funding for these activities allowed under CDC funding guidance. For example, in June, California announced a Digital COVID-19 Vaccine Record that offers an option for individuals to securely access their immunization record from the state’s IIS. Other states have developed portals, such as those facilitated by Docket or MyIR in Arizona, Louisiana, Maryland, Mississippi, North Dakota, Washington and West Virginia that allow individuals to access their immunization history and receive reminders for future vaccinations.


The COVID-19 pandemic has renewed urgency for states to invest in public health infrastructure through newly available federal funding streams. With COVID-19 vaccine distribution efforts revealing the need for significant investment in IIS capacity and substantial federal funding available to support modernization efforts, states can consider upgrading their IISs to improve standardization and data quality, facilitate secure data exchange with authorized partners and support consumer access to vaccination records.

Despite new funding for COVID-19 response and recovery, there is also a need for federal guidance and leadership to address current fragmentation and variability in IISs that limit information exchange both within and between states. As federal and state leaders continue to develop plans for modernizing public health data systems, Governors can call on federal leaders to work with stakeholders across the immunization community to develop a vision and national policy framework for immunization data infrastructure that can identify current gaps and improve real-time data sharing between public health and health system partners.

This brief contains an appendix of “Federal Funding Streams that may be Used to Support Immunization Infrastructure.”


We thank the organizations and individuals who contributed to and provided feedback on this brief, including the Association of State and Territorial Health Officials; Claire Hannan and Katelyn Wells, Association of Immunization Managers; and Rebecca Coyle and Mary Beth Kurilo, American Immunization Registry Association.

Contributing Authors

Duke-Margolis Center for Health Policy

  • Katie Greene, MPP
    Assistant Research Director
  • Katie Huber, MPH
    Policy Analyst
  • Mark McClellan, MD, PhD
  • Kirk Williamson, MPH*
    Senior Policy Analyst

National Governors Association

  • Michelle LeBlanc, MPH
    Policy Analyst
  • Brittney Roy, MPA
    Program Director, Public Health

National Academy for State Health Policy

  • Johanna Butler
    Policy Associate
  • Christina Cousart, MPH
    Senior Policy Associate
  • Hemi Tewarson, JD, MPH
    Executive Director
  • Sandra Wilkniss, PhD
    Senior Director of Population & Public Health

*Kirk Williamson contributed to this paper while at Duke-Margolis.