All we can do is monitor him over the years

Dr Dick Stevens, Royal Manchester Children's Hospital

The boy received the transfusion at the Royal Manchester Children's Hospital in Pendlebury four years ago.

The hospital's haemophilia director Doctor Dick Stevens said he had informed the boy's family, who will now face an anxious wait to see if he contracts vCJD.

The boy's parents are said to be angry that their son was not given a transfusion of a synthetic blood substitute, which would have been risk-free, but about three times more expensive.

'Hypothetical risk'

Now there is a legal requirement for children under 16 to be given the substitute, rather than a natural blood product, but the hospital said that when the boy received his transfusion that law had not yet come into force.

Dr Stevens told BBC Radio 5 Live: "The boy in question received a product called factor eight ... from a normal British blood donor.

"A the time of donation [the donor] was perfectly well, but has subsequently developed nvCJD.

"The donation was given to the boy before the government made a decision that the risk free factor eight ... was available

"We have now been able, for the last three years, to get what we call the recombinant factor eight for haemophiliacs, which theoretically is a much safer product.

'No evidence'

"The doctors and nurses dealing with haemophilia would support this approach very strongly."

Dr Stevens admitted that he could not guarantee the boy, who is unaware of the situation, would not develop CJD in the future.

"It's a hypothetical risk," he said.

"Obviously I feel for the anxieties and we would do our best to support them through this.

"All we can do is monitor him over the years."

The Department of Health has said there is no evidence that vCJD has ever been transmitted through blood or blood products and any link is theoretical.

Their statement came following a scare earlier this year in which it was feared haemophiliacs may have been exposed to blood plasma from a donor later found to have been infected with vCJD.