TUESDAY DECEMBER 18 2001

Polio doses 'very unlikely' to be a risk for past recipients

BY NIGEL HAWKES, HEALTH EDITOR

ABOUT a third of the oral polio vaccine used in Britain between 1986 — when BSE first appeared — and 2000 was produced with the aid of material from British cows.

The vaccine was grown using foetal calf serum, a nutritious culture medium from herds that might have been contaminated with BSE. The batches of vaccine were made by Wellcome until 1991 and subsequently by Medeva. There is no evidence that they were contaminated, but the possibility exists.

The Government’s Spongiform Encephalopathy Advisory Committee (SEAC) says that up to 60 million doses of the vaccine were produced from cultures that might have been contaminated. Millions of people — about a third of all those vaccinated since BSE appeared — have been given the potentially contaminated vaccine.

If the 113 people who have contracted vCJD are typical of the public as a whole, it would be expected that about 30 to 40 of them would have been recipients of the suspect vaccine.

The fact that two have actually been found to have had it cannot, therefore, be seen to be surprising or significant. They lived in the same area and were vaccinated at the same time, in 1994, so it is not surprising that the vaccine came from the same batch.

The finding would become significant only if there was something special about this particular batch that made it more likely to have been contaminated.

SEAC looked at the proportion of the vCJD victims who had been given the Wellcome/Medeva vaccine, and found it was no higher than in the general public.

But because patients’ records did not always include batch numbers, that comparison cannot address the question of whether there may have been a rogue batch.

This is why SEAC suggests that in future batch numbers should be logged by GPs. Had this been done in the 1980s a more complete analysis would now be possible.

Polio is an oral vaccine, so is much less likely to have transmitted vCJD than injected vaccines grown using the same foetal calf serum, of which there were several in the early 1990s. Injection is a more potent route of transmission than ingestion.

We know that beef was contaminated, and almost everybody ate it. We do not know that polio vaccine was contaminated, and there is no evidence of a generally raised risk among those who were given the suspect vaccine.

SEAC sees no reason to modify the Committee on Safety of Medicine’s advice that it is “very unlikely” that the foetal calf serum used to grow the vaccines could pose any vCJD risk.

Professor Liam Donaldson, the Government’s Chief Medical Officer, has described the risk as “incalculably small”. SEAC sees no reason to modify that judgment.

Click here for BT Business.  Connections that get results.

Copyright 2001 Times Newspapers Ltd. This service is provided on Times Newspapers' standard terms and conditions. To inquire about a licence to reproduce material from The Times, visit the Syndication website.