Despite little evidence that new variant Creutzfeldt-Jakob Disease (nvCJD) might be transmitted by blood or plasma, a US Food and Drug Administration (FDA) advisory panel voted June 2nd to prohibit donations from people who resided in or traveled to the UK during 1980–96. The panel is now considering whether the time spent in the UK should amount cumulatively to six months or as long as five years.

The recommendation by the Transmissible Spongiform Encephalopathies (TSE) Advisory Committee, which would put a squeeze on the already tight US blood supply, was weighed against the potential for an epidemic.

The panel comprised eminent TSE researchers, including Paul Brown of the National Institute of Neurological Disorders and Stroke, and Nobel prize-winner Stanley Prusiner of the University of California, San Francisco. Both voted for a ban. "I don't think the availability of donors is a reason to vote yes or no," says Prusiner. "We're dealing with a disease that is universally fatal."

Senior TSE scientist, Robert Rowher of the Veterans Affairs Medical Center in Baltimore, Maryland, urged the panel to prohibit donations. "I am very concerned we may be facing the grave possibility of an epidemic of new variant CJD," he says. But admits, "what we're doing is mitigating exposure to a certain extent, but to what extent, we don't know."

Brown noted there has been no BSE in US cattle, and no blood-borne transmission of nvCJD in the UK. The UK prohibits plasma donations by those who ate beef during the peak BSE exposure; whole blood is still accepted because it is harder to import sufficient supplies. Brown points out that the incubation of nvCJD is still an unknown, as is whether the disease is really an instance of species-jumping or a new entity.

Bruce Chesebro, a TSE researcher at the Rocky Mountain Laboratories, Montana, told Nature Medicine he would have had a hard time voting on a blood policy, because "The evidence for transmission of any TSE by blood is very limited." He also explains that it is difficult to detect infectivity in blood, and that BSE has not been found in the spleen or other lymphoid organs. However, BSE is different than scrapie, so it may act differently in humans, he adds.

The blood banking industry insists that without definitive evidence, there should be no donor deferral. According to government estimates, by 2000, the US is expected to have 11.7 million units of red cells, but a demand for 11.9 million units. An American Red Cross-led survey of 9,000 recent donors found that 22.6 percent had been in the UK at least 1–3 days during 1980–96. Seventy-two percent had eaten beef while there. If those who stayed a cumulative six months were deferred, 2.2 percent of the US blood supply would be lost.

The FDA panel's suggestions are being weighed by the Department of Health and Human Services (HHS), and a new policy incorporating HHS input is expected to be issued by the FDA in the near future.