Jonathan Simms (1 June 1984 – 5 March 2011) was a man from Belfast, Northern Ireland, who contracted variant Creutzfeldt–Jakob disease (vCJD) in his late teenage years. He was given a post-diagnosis life expectancy of one year, similar to that of other young people who were diagnosed in the same age bracket. However, due to his receiving experimental treatment for the disease (of pentosan polysulfate), he lived for another ten years after diagnosis, although his higher functions were severely limited.