Immunization Calculation Engine (ICE)

A state-of-the-art open source software system that provides clinical decision support for immunization 

ICE Web Service

The ICE Web Service evaluates a patient’s immunization history and generates the appropriate immunization recommendations for the patient. ICE can be deployed in diverse technical environments and easily integrates with third-party clinical systems such as Immunization Information Systems (IIS), Electronic Health Records (EHR), Personal Health Records (PHR), and Health Information Exchanges (HIEs).

In 2021 Immunization Calculation Engine (ICE) was chosen by the Digital Public Goods Alliance (DPGA) as an innovative openly licensed technology and listed in their Digital Public Goods registry.

Why Choose ICE?

  • No license fee to use this open source software
  • Supports all routinely administered vaccines for children and adults
  • Compliant with the Advisory Committee on Immunization Practices (ACIP) clinical guidelines
  • No vendor lock-in through full access to source code
  • Maintained through an open and collaborative process
  • Flexible deployment options
  • Scalable for high performance

ICE Support & Services

No commercial software or commercial services are required to utilize the open source Immunization Calculation Engine (ICE) software system. However, if your organization would like assistance with ICE, then HLN can offer a variety of customized services to meet your specific needs. HLN’s ICE related service offerings include:

Develop and maintain new or existing systems

Technical Support

Create technical documentation, and collaborate with your IT staff to integrate ICE 

Develop and maintain new or existing systems


Customize or maintain an immunization schedule on behalf of your organization

Develop and maintain new or existing systems

Hosted Service

Clinical and public health systems can securely connect to the ICE web service over the internet

A simple application, called “ICE Client” is available to submit sample patient data to the ICE Web Service and see the evaluations and recommendations the ICE Web Service returns. 
Download ICE and the accompanying implementation guide to integrate ICE with your system.
Sign up for ICE Announcements and receive notice of new and upcoming releases.
For more information about ICE, contact

HLN was awarded the 2017 Upshot Award for Excellence in Vaccine Supply, Access, and Use by the U.S. Department of Health and Human Services National Vaccine Program Office (NVPO) for its ICE Open Source Immunization Forecaster.

“HLN Consulting’s efforts on the Immunization Calculation Engine (ICE) are impressive. This powerful tool-including its open-source nature and seamless integration into clinical workflows-holds great promise for improving clinical decision-support and ultimately vaccination rates. Thank you for daring to innovate, collaborate, and lead in an area that is not only complex but constantly evolving.”
Dr. Jewel Mullen, Principal Deputy Assistant Secretary of Health.