“Prion diseases are a class of rare and fatal disorders that can be acquired or inherited,” says Mahnia Madan, OD, of Vancouver, British Columbia. She notes that the most common form of prion disease is Creutzfeldt-Jakob disease (CJD), which causes neurodegeneration, motor dysfunction, dementia and eventually death within one year.

Eighty-five percent of CJD cases are sporadic, 11% are inherited and 4% are acquired. The latter has mainly been documented in the United Kingdom due to contact with contaminated meat products or exposure to infected tissue during a medical procedure, such as pituitary growth factor administration, blood transfusion, dura mater allograft and corneal transplantation.^1,2

Successful full-thickness graft with running suture. Click image to enlarge.

Discussion

With more than 30,000 corneal transplants performed in the United States each year, a statistical analysis estimated the risk of prion transmission to be extremely low at only 0.045 cases per year.³

When it comes to CJD transmission, current evidence supports that sporadic CJD is not transmitted by blood transfusion while acquired cases can be. Identified occurrences in the United Kingdom have been linked to consumption of meat products contaminated with prions (mad cow disease).

In 1999, several countries implemented a series of precautionary measures which included a ban on the use of United Kingdom-sourced plasma to produce immunoglobulin products. However, this ban was re-evaluated and lifted in 2021.

With the impositions of the Eye Bank Association of America’s medical standards and the FDA’s disease prevention and donor selection criteria, the risk of CJD transmission is considered negligible and should not disqualify affected patients from donating blood.