A large study of Scandinavian blood donors and transfusion recipients showed no evidence that dementia-type disorders are transmitted through blood transfusion. The findings are published in Annals of Internal Medicine.
Several neurodegenerative disorders, including Alzheimer and Parkinson disease, are characterized by an aggregation of misfolded proteins in the brain. This protein aberration can be passed from humans to healthy laboratory animals through the injection of diseased brain tissue from human sufferers, prompting fears that the diseases could also be passed from human to human through blood transfusion.
Researchers studied nationwide registers of blood transfusions in Sweden and Denmark between 1968 and 2012 to investigate possible transmission of dementia disorders. They identified more than 40,000 patients who had been given blood from donors diagnosed with one of the studied dementia diseases within 20 years of having given blood. After a maximum follow up of 44 years, the researchers compared those patients with the 1.4 million patients who had not received blood from donors with a subsequent diagnosis of one of the dementia diseases. The patients in both groups had exactly the same likelihood of contracting one of these diseases, which clearly showed that neurodegenerative disorders cannot be transmitted through blood transfusion.