John Collinge was at the eye of the storm when cases of new variant Creutzfeldt–Jakob disease (nvCJD) began to appear in the United Kingdom in the late 1990s. An expert in prion diseases, he demonstrated that the prion strain in nvCJD matched that from bovine spongiform encephalopathy — BSE, or ‘mad cow disease’ — in cattle and has since developed the first blood test for early diagnosis.

Prions are misshaped proteins that accumulate in the brain and cause degeneration: John was one of the first to accept this unusual ‘protein-only’ mode of transmission. His studies of the molecular basis of prion diseases have led to potential therapies for these and related neurodegenerative conditions such as Alzheimer’s.

John’s demonstration that nvCJD was caused by eating BSE-infected beef led to changes in food safety policy, and his blood test is now used to screen donated blood for prions. For his services to medical science, he was made a CBE in 2004.