OpenAI Updates ChatGPT Health Intelligence With GPT-5.5 Instant, Now Matches Frontier Thinking Models on Medical Evaluations

OpenAI announced June 18 that GPT-5.5 Instant now delivers substantially improved health intelligence across ChatGPT, with gains in recognizing when urgent care may be needed, appropriately flagging uncertainty, and making complex medical information more accessible. On OpenAI's most challenging internal health evaluations, GPT-5.5 Instant now performs at a level comparable to its frontier Thinking models — a material jump from prior versions. More than 230 million people turn to ChatGPT weekly with health questions, making this accuracy improvement one of the broadest-reach AI capability updates of the year.