DEAR DR. ROACH: I lived in England in 1985-1986, during the mad cow disease outbreak. Since then, I have been ineligible to give blood. It is one of the few questions they ask. This has been 35 years and, obviously, I don’t have and have never had the disease itself. Is this still a valid reason to rule me out as a blood donor? — B.R.
ANSWER: Variant Creutzfeldt-Jakob disease was epidemic in the United Kingdom (and to a lesser extent, Ireland and France) from 1981 to 1996. By preventing blood donation from people who lived in the U.K. for more than six months during that time period, it is estimated that 90% of future vCJD could be prevented in the U.S.
Incubation periods of 40 years have been reported for a similar disease, kuru, which is why the prohibition against blood donation remains. However, the absolute risk is very