On May 22, 2026, HLN released a new version of the open-source Immunization Calculation Engine (ICE) software with several clinical logic and technical enhancements to improve clinical decision support accuracy and service. Clinical refinements include updates across seven vaccine groups to improve alignment with guidelines and expand vaccine support. This release introduces a new wiki URL mapping feature to improve logic transparency, updates time zone formatting to enhance system compatibility, and streamlines the codebase to make deployment and maintenance easier.
What’s New in ICE
Clinical logic updates
- Hepatitis B: Added support for an interval grace period in the 3-dose Child/Adolescent Series and the 4-dose Child/Adolescent Series. In the 4-dose Child/Adolescent Series, added the “extra dose” reason to the evaluation of target dose 3, to distinguish this dose from other valid doses in the series.
- HPV: Modified intervals to improve alignment with MMWR guidelines; this includes added support for a shorter dose 1 to dose 3 evaluation interval when target dose 3 is administered prior to 12/16/2016.
- Influenza: Added support for a new non-US vaccine: Influenza, Southern Hemisphere, high-dose, trivalent, PF (CVX 337).
- Pneumococcal: Lowered the absolute minimum age for PCV 21 (CVX 327) from 19 years – 4 days to 6 weeks – 4 days; added support for this vaccine in the Pneumococcal Child Series. Modified the Pneumococcal Child Series 4-dose Series Exception Rules to support the return of the earliest date when these exceptions apply.
- Polio: Added support for an additional valid “extra dose” in the Polio 4-dose series and the Polio fIPV series when dose 4 and dose 5 in these respective series are administered >= 8/7/2009 and before 4 years – 4 days of age.
- Zoster: Added support for series completion prior to age 50 years.
Technical improvements
- New Feature for Logic Traceability: Enabling the new “output-vaccine-group-rules-artifact” embeds vaccine group wiki URLs directly in shot evaluations and forecasts, making it easier to audit ICE outputs and trace them back to their underlying logic rules.
- Enhanced Downstream Compatibility: Date output time zones have switched from ISO 8601 extended (-04:00) to basic (-0400) to prevent formatting conflicts and ensure seamless, error-free integration with downstream systems.
- Refactoring and maintenance updates to reduce deployment overhead and improve long-term system stability.
See the latest logic updates in action using CDS Insight, a free tool that allows users to interact with HLN Consulting’s locally hosted instance of the latest version of ICE. Simulate patient scenarios and receive immunization evaluations and recommendations under the latest ICE rules.
Please see the Release Notes for additional details and download ICE v2.57.1 today.
Questions? Please reach out to the ICE team at ice@hln.com.