Immunization Information Systems

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 your practice the opportunity for confidential, secure, centralized, and immediate access to immunization records if you choose to participate as an authorized provider. IISs can be useful in identifying under- and over-immunized children, monitoring community immunization rates, identifying coverage gaps and improving vaccination rates.

Key Points to Know

  • Use of an IIS benefits patients, their families and your practice. Use of a fully functional IIS reduces costs, streamlines your practice work flow and improves patient care.
  • There are common standards for IISs. 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 took effect in 2019.
  • There are core data elements collected by an IIS, which are critical for record exchange purposes, client de-duplication, vaccine management, immunization status evaluation, reminder / recall, and data analysis or use purposes.
  • State law requires that information in an IIS be kept confidential, though reporting of immunizations to an IIS is exempt from the Health Insurance Portability and Accountability Act of 1996 (HIPAA) Privacy Rule since it is considered a public health activity. 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.

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

Last Updated



American Academy of Pediatrics