Fears raised over new vCJD wave tells us that the first wave of "mad cow" victims all shared a common (42% of the UK) gene variant called MM. New cases suggest a new wave in non-MM persons.
We don't know if this '2nd wave' will be more common as well as later onset, but the current guesses are roughly the same frequency -- meaning rare for the population as a whole.
I wonder why we don't see more retrospective reviews of the science of these historic disease outbreaks. We ought to have a tradition of five and ten year historic reviews of things like "Mac Cow" (variant CJD) and SARS-associated Coronavirus disesase.
How about it science writers? Just look back in the NYT's archives and find out what mysterious diseases were big 10 years ago. Do it every January 1st, and then put out a retrospective with the best current science. Could be a career.