There was no risk to patients of contracting new variant CJD from an oral polio vaccine, the Chief Medical Officer has said.

The vaccine, which used calf foetus serum, was withdrawn as a precaution in October 2000 after fears that it could be contaminated with BSE.

But an investigation by Professor Sir Liam Donaldson, Chief Medical Officer for England, found there was no infection risk to patients who were given the vaccine.

A separate report by the Committee on Safety of Medicines has also said that although many vaccines use bovine products in their manufacture there was an "incalculably small risk" of humans contracting vCJD.

The vaccines that protect both children and adults from harm are manufactured to the highest and safest standards

Hazel Blears, health minister

The CMO said in his report on the removal of the oral polio vaccine from use: "The withdrawal was justified on a precautionary basis although there were no public health issues."

However, the government admitted that the House of Commons was misled about whether products complied with guidance.

But Health Minister Hazel Blears said that had happened because of inaccurate advice.

This was given by the Medicines Control Agency because of misinterpretations of the guidelines governing the use of animal products in medicines and problems tracking the history of vaccines, she said.

In a statement to the Commons, she apologised for misleading MPs: "It's important to provide clear assurances to the public that the vaccines that protect both children and adults from harm are manufactured to the highest and safest standards."

Inaccurate reassurance

The errors arose because of confusion over when bovine material can be used in the complicated vaccine manufacturing process.

Twenty-six of the 95 licensed vaccines in the UK do not comply with existing regulations, but have been assessed to be safe by experts.

New European regulations are being introduced to spell out how the material can be used, and all vaccines will comply with them, said Ms Blears.

Hundreds of thousands of people were given the oral polio vaccine manufactured by Medeva.

The plant owned by Medeva was bought by Powderject, which no longer makes the vaccine.

It was withdrawn after the Department of Health discovered the manufacturers' assurances over the calf foetus serum were inaccurate.

Vaccines now use bovine material from Australia, New Zealand, the USA or Canada.

Breach

Oliver Heald, Conservative health spokesman welcomed the reassurances given over the vaccine safety.

But he added: "Of course, it does seem that the Medicines Control Agency advice to ministers was comprehensively inaccurate and has led to many UK vaccines being in breach of EU guidance."

Dr Evan Harris MP, Liberal Democrat health spokesman said: "Liberal Democrats are satisfied, on the information provided, to support the Government and the Chief Medical Officer's assertion of the overwhelming benefit of the current vaccination programme compared to any safety risk.

"Parents should continue to vaccinate their children."

But he added there were still many questions for the government to answer.

"Why has it taken nearly two years since the government first suspected that parliament had been misled for the record to be corrected?"