Immunization Information Systems


​​​​Immunization Info​rmation Systems​

Updated April 2019

What Are IISs, and Why Do We Need Them?

Immunization information systems (IISs), otherwise known as registries, are confidential, population-based, computerized databases that record all immunization doses administered by participating providers to persons residing within a given geopolitical area. They offer an opportunity for confidential, secure, centralized, and immediate access to immunization records for authorized providers. IISs can be useful in identifying under- and over-immunized children, monitoring community immunization rates, identifying coverage gaps and improving vaccination rates.

How Can You Benefit from Using an IIS in Your Practice?

Use of a fully functional IIS reduces costs, streamlines practice work flow and improves patient care. An IIS can:

  • Facilitate work flow and help manage administrative costs by tracking inventory and distribution, supporting vaccine ordering, and other vaccine-related business processes.
  • Eliminate the need for and costs of coordinating point-to-point immunization record transfers between service providers.
  • Reduce data entry time and improve data accuracy and completeness with the ability to submit data electronically from the EHR to the IIS, and import patient immunization records from the IIS to the electronic chart.
  • Improve patient immunization rates and Healthcare Effectiveness Data and Information Set (HEDIS) scores, which may be tied to Pay for Performance (P4P) programs.
  • Decrease vaccine administration errors using robust vaccine forecasting algorithms.
  • Enhance patient reminder and recall efforts.
  • Decrease missed opportunities to immunize.
  • Allow the patient immunization record, a core component of the pediatric medical history, to be truly portable and follow the patient regardless of service location by generating affordable, accurate records for patients, schools, and child care.
  • Identify vulnerable patients during an outbreak of a vaccine-preventable infection.

Note: Direct practices expenses associated with clinical staff time for input of information into an IIS is included in the relative value unit (RVU) published for the Immunization Administration (IA) Current Procedural Terminology (CPT) code on the Medicare Resource-Base Relative Value Scale (RBRVS). 

Are There Common Standards for IISs?

Yes. Immunization Information System (IIS) Functional Standards were first issued by the Centers for Disease Control and Prevention (CDC) in 1997 and have been maintained and updated since that time. The most current IIS Functional Standards, v4.0 take effect in 2019.

What Information Is Entered Into an IIS, and How Is It Protected?

Core data elements are critical for record exchange purposes, client deduplication, vaccine management, immunization status evaluation, reminder / recall, and data analysis or use purposes. Required and optional elements may include:

  • the patient's first, middle, and last name
  • date of birth
  • sex
  • race
  • ethnicity
  • birth order
  • birth state/country
  • mother's first, middle, last, and maiden name
  • vaccine type
  • vaccine manufacturer
  • vaccination date
  • the patient's alias
  • address
  • phone number
  • social security number
  • father's name
  • vaccine provider
  • and VFC program eligibility

State law requires that information in IISs be kept confidential, though reporting of immunizations to an IIS are exempt from the Health Insurance Portability and Accountability Act of 1996 (HIPAA) Privacy Rule since it is considered a public health activity. IISs must protect the privacy of all users, including children, families, and providers. According to standards set by the CDC, all IISs are required to have a written privacy policy that clearly defines notice of inclusion in the IIS, access to, and use and disclosure of IIS data. For more information, ask the IIS in your area for a copy of their confidentiality policy.

How Do IISs Benefit Patients and Their Families?

The benefits for patients and their families are both practical and potentially lifesaving. An IIS can:

  • Provide the most up-to-date immunization records for schools, child care, and sports teams.
  • Provide families with their child's immunization records for personal safekeeping.
  • Ensure that patients get only those immunizations that are needed.

Where Can I Find Information About My State or Jurisdiction's IIS?

The CDC has contact information on its IIS State/Territory/Registry Staff—Main and Technical Contacts page

IIS Resources


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