BBC Thursday, 12 April, 2001, 11:16 GMT 12:16 UK

'Super-measles' warning

Vaccination is the key to wiping out measles, says an expert Tougher, vaccine-resistant strains of measles could sweep the world unless more children get vaccinated, says a top scientist.

Dr Claude Muller, from the National Health Laboratory in Luxembourg, told New Scientist magazine that the virus was known to have the ability to mutate rapidly.

Patchy vaccination coverage was likely to encourage the selection and survival of more resistant strains, he said.

The worldwide immunisation programme should be stepped up to knock out resistant strains before they get a foothold, he said.

There are some fears in Britain that measles could re-emerge in areas where measles vaccination uptake is poor, particularly in the inner cities.

Here, an outbreak would expose thousands of children to some risk of disability, or, in a very few cases, death.

Worries over the safety of the triple MMR vaccine has been partly blamed for the fall in vaccination rates.

In the first quarter of 1995, there were more than 2,600 notifications of measles in England and Wales, compared to fewer than 500 in the final quarter of 2000.

In fact, only 73 cases of measles were confirmed by laboratory tests in the whole of 2000.

A spokesman for the Public Health Laboratory Service said that vaccine-resistant strains had yet to emerge here.

He said: "Although there is some diversity of strains of measles in the UK, the range is relatively limited.

"If you get measles once here, you are unlikely to get it again."

Significant killer

However, elsewhere in the world, measles remains a significant killer of children - there are almost 1m child deaths a year as a result of the infection.

The World Health Organisation recently set a worldwide target of getting 90% of children immunised against measles virus.

With that target nowhere in sight despite almost overwhelming success in polio vaccination initiatives, the latest target - no less daunting - is to halve measles deaths by 2005.

Dr Muller's team reports that some strains of measles virus circulating in Africa appear to have acquired a considerable level of resistance to the standard measles vaccine in use in the continent.

At least half the immune system antibodies produced inresponse to the vaccine have no effect on these strains.

The scientist is urging the WHO and governments to accelerate vaccination programmes to make sure these strains do not have the chance to develop even more resistance.

"We have a window of opportunity," he said. "We know this family of viruses mutates readily."

Bjorn Melgaard, the head of vaccines at the WHO, said that the new target of halving deaths should be achievable.

"It was deliberately chosen to be feasible. But we may not be able to eradicate measles, and it might not even be worth it to try."

-- Anonymous, April 12, 2001