Scientists examine CJD 'link' to polio vaccine

Senior Government advisers sought to head off a potential public health scare yesterday after two people with the human form of BSE were found to have shared the same batch of polio vaccine.

Although the two victims of variant Creutzfeldt-Jakob disease (vCJD) both took the oral form of the vaccine, made using bovine blood, scientists believe the cases are a coincidence.

Professor Peter Smith, chairman of the Spongiform Encephalopathy Advisory Committee (Seac), revealed that an investigation by scientists has failed to find evidence of a link between other cases of vCJD and the polio vaccine.

However, Seac scientists are concerned that even raising the possibility of a link could turn parents away from childhood immunisation programmes, which have already suffered bad publicity over alleged health risks.Deidre Cunningham, a public health specialist and new member of Seac, said: "An absolutely infinitesimal risk was absolutely no justification for ruining a vaccination and immunisation programme that actually does protect people's health."

The two vCJD patients are part of a group of five "geographically-associated cases" in the Southampton area. Both were given oral polio vaccine from a batch distributed in 1994, six years before the vaccine was banned. Each batch consisted of between 70,000 and 80,000 doses and was part of a larger consignment of about five million doses each made by an identical process of growing the vaccine in blood serum drawn from foetal calves.

The Department of Health recalled the vaccine in October 2000 because it breached European guidelines banning the use of foetal calf serum from countries affected by BSE.

However, a comparison of patients with vCJD and healthy people failed to find evidence to suggest that the vaccine could have caused the transfer of BSE from cattle to humans.

Professor Smith said: "Looking at the cases as a whole, there is really nothing to implicate polio vaccine [as a source of vCJD]." Both patients lived in the Southampton area, were of a similar age and could have shared many other features of their lifestyle. Both received the polio vaccine as young adults.

"It's highly likely that they would have had polio vaccine from the same batch – that's why we didn't attribute any particular significance to this," he said.

Ray Bradley, a veterinary scientist and member of Seac, said tests had failed to find any evidence that BSE could be transmitted in the blood of adult cattle, let alone foetuses. "Foetal calf serum is used in most viral vaccines and there have been millions of vaccines prepared in this manner and no evidence whatsoever [of] any transmission of BSE."