Scientists have found evidence to suggest that more people could be harbouring the human form of BSE than previously thought.
The scientists studied over 12,000 tissue samples
Researchers at Plymouth's Derriford Hospital and the CJD Surveillance Unit tested 12,674 appendix and tonsil samples - three showed signs of vCJD.
Extrapolating their findings to the whole population, they estimated that 3,800 Britons may harbour the disease.
The findings are published in the Journal of Pathology.
A total of 141 people have died from vCJD in the UK since the disease emerged in 1995.
Scientists have been suggesting that the number of deaths from the disease had peaked.
A recent study by researchers at Imperial College London predicted the disease would claim no more than 540 lives.
The scientists who carried out this latest study said their findings "need to be interpreted with caution".
"There is still much to learn about vCJD and presence of the protein in these tissue samples does not necessarily mean that those affected will go on to develop vCJD," said lead researcher David Hilton.
Professor James Ironside of the National CJD Surveillance Unit in Edinburgh said the findings suggested some people could carry the disease without ever showing any symptoms.
But he added: "I think the findings do have to be taken seriously. Generally, one has to be cautious about interpreting these data, but they may indicate that there are
people who are not infected in the normal way but could represent a source of
The study comes as the Medical Research Council told BBC News Online that a long-awaited trial to test potential treatments for vCJD could start within weeks.
It will examine if an anti-psychotic called quinacrine or an unlicensed drug called pentosan polysulphate can help people with the disease. Both have shown some promise in patients.
Meanwhile, the Health Protection Agency is in the process of collecting 100,000 tonsil samples which will be tested for signs of vCJD.
"The larger scale of the study should provide better estimates of the number of people who may be affected," said Professor Pat Troop, the agency's chief executive.
A leading expert on vCJD said the latest estimates might be too low.
"I find these results very concerning," said Professor John Collinge, head of the MRC Prion Unit at St Mary's Hospital, in London.
"Our experience is that looking at appendix samples will underestimate the true picture."
He suggested the government should look again at whether surgeons should use disposable instruments in operations where there may be a risk of transmission, such as the removal of tonsils.
A Department of Health spokesman said it had "already put in place measures to reduce any risk of possible transmission of the disease via blood products and surgical instruments".
Don Simms, whose son Jonathan has vCJD, said the latest study showed that scientists simply did not know how many people had the disease.
"The fact is we just don't know how many people are affected. We need to find out," he told BBC News Online.