OpenAI: GPT-5.5 Instant Health Intelligence Matches Frontier Models, Now Free
OpenAI
OpenAI published an update on June 18, 2026 showing GPT-5.5 Instant's health performance now matches frontier models on HealthBench Professional, with a 71% drop in factuality issues versus GPT-5.3 Instant. Physician evaluators rated model responses across 3,500 clinical scenarios covering accuracy and communication. The model is available to all free ChatGPT users.
Why it matters
Over 230 million weekly ChatGPT users gain access to frontier-grade health AI. The 71% factuality improvement matters most for the high-stakes medical domain.
Importance: 2/5
Notable performance improvement and expanded access, but no new model — incremental health-domain update to an existing model family.