Blood filter to protect patients from vCJD – but only for the young

Health advisory committee recommends the adoption of a newly developed blood filter for transfusion patients aged under 13
Blood tests at Christies in Manchester
Photograph: Howard Walker/Manchester Evening News

All red blood cells given as transfusions to children under the age of 13 should be filtered to remove the infection that cause the fatal brain disease vCJD, a government scientific body has recommended.

But the proposal by the Advisory Committee on the Safety of Blood, Tissues and Organs (SaBTO) has been criticised for failing to provide the same level of protection to the rest of the population.

The Department of Health is considering the comittee's advice. Purchasing the necessary medical equipment to filter all the UK's blood supplies would cost up to £75m.

Variant Creutzfeldt-Jakob disease (vCJD) is caused by mutated proteins, known as prions, that infect the victim's brain, forming sponge-like holes in the tissue and causing a fatal neurodegenerative disorder.

So far 166 people have died in the UK, fewer than initially feared, following the emergence of the condition in the mid-1990s. All the early cases were due to the consumption of beef contaminated by BSE (bovine spongiform encephalopathy), a similar condition found in cows.

But vCJD can also be transmitted to humans through blood transfusions from people who show no outward sign of carrying the disease at the time. There have been five proven cases of such transmission already in the UK.

The prevalence of vCJD infections in the general population is unknown, but one estimate, based on tests on removed appendixes, has suggested that as many as one in 4,000 of the population could be infected.

Minutes of the most recent SaBTO meeting, on 27 October, show that members were shown data from the latest evaluation of the filtration system. The committe recorded that it was, "satisfied that there is now sufficient evidence that this particular filter reduces infectivity".

SaBTO recommended that "filtered red cells be provided to those born since 1 January 1996, subject to satisfactory completion of [a further] clinical trial".

The decision not to deploy the P-Capt (Prion Capture) prion reduction filter system to clean blood for those over the age of 13 has puzzled and disappointed the manufacturers. Iwona Walicka, project manager at MacoPharma which manufactures and distributes the filter said: "1.8 million blood units are donated in England each year and yet we have no idea how many blood donors are incubating the vCJD prion, which can lie dormant for decades.

"What we do know for sure is that vCJD is a devastating disease, for which there is no cure, and that it can be transmitted by transfusion of infected blood/blood products. [This filter] has been extensively and independently tested for three years: it works, it's safe and it's available now. Its adoption makes sense: because everyone has a right to safe blood.

"The highest transmission risk for vCJD [now] is contaminated blood/blood products and to date there have been five confirmed cases of such transmission in the UK," she added. "Treatment of red cell concentrate with the P-Capt filter is an affordable means of removing vCJD prion and the unit cost of filters will decline sharply when they are used to treat all blood donations."

Judy Kenny, whose husband Deryck died six years ago, has also criticised the government for failing to spend sufficient funds for universal blood filtering. Deryck was the first patient known to have contracted the condition through infected blood.

She has said: "As a nurse I've seen every sort of death and vCJD is horrible. It's the worst death. I understand the financial pressures in the NHS, but as a wife who saw my husband die from this terrible disease I would do anything to stop it happening again ... As I see it, anything that can stop this disease occurring would be money well spent."

A spokesman for the Department of Health said: "[We are] grateful for this advice from SaBTO and are currently considering this recommendation with NHS Blood and Transplant."