Isobella Thomas's family is one of 2,000 families who say their lives have been ruined by the MMR vaccine.

Her sons Michael, nine, and Terry, seven, developed signs of autism and suffered bowel problems after being inoculated as toddlers.

Mrs Thomas, from Brighton, says Michael became seriously ill hours after his injection and in the following months, became withdrawn, antisocial and affected by stomach cramps.

She took him to her GP regularly but was told his behaviour was not a cause for concern.

It was only when her second son was immunised and reacted the same way that she realised something was wrong.

Mrs Thomas is now a member of the pressure group Jabs which aims to promote understanding about immunisations and offer basic support to any parent whose child has a health problem following vaccination.

The group wants comprehensive information for all parents to make an informed decision on the benefits and risks of vaccination.

The news is a blow to those who are hoping for a treatment which can do more than slow down the progress of the incurable disease.

The vaccine was being tested in four European countries and 11 hospitals in the US.

The trials were designed to test the safety of the formula before moving on to see how effective it was at halting Alzheimer's.

However, 12 people out of the 360 volunteers - all with mild or moderate cases of the disease - became seriously ill with inflammation of the brain.

They had symptoms which ranged from fever, headache and vomiting, to muscle weakness and seizures.

All are being treated and are "responding appropriately", said the pharmaceutical company Elan, which had been developing the vaccine.

'Puzzling'

The idea of the vaccine was to prime the body's own immune system to attack and destroy a body chemical called beta amyloid, the ingredient of "plaques" which appear in great numbers in the brains of Alzheimer's patients.

Europe's biggest drugs firm said it was cooperating fully with the investigation and added the accusations stemmed from the period between 1997 and 1999, before Glaxo Wellcome merged with SmithKline Beecham in 2000.

"These are allegations we take extremely seriously ... We are investigating this internally and we will review this on a European wide basis," Christopher Viehbacher, President of European Pharmaceuticals at GlaxoSmithline told the BBC's World Business Report.

Munich's chief prosecutor Manfred Wick said GSK offered money, free trips and other benefits to about 4,000 hospital doctors, and that there were suspicions of bribery and tax evasion.

The prosecutor said cash sums ranged from 50 to 25,000 euros (£30 to £15,400).

However, other experts are still doubtful whether the virus - or the vaccine - can be blamed.

Batches of polio vaccine tainted with "simian virus 40" (SV40) were given between 1955 and 1963.

This was because monkey kidney cells were used in the jab's production process.

Approximately 30m people may have been given the contaminated vaccine between these dates.

It has also been alleged that the virus which causes Aids was passed from primates to humans in this way, although close examination of frozen samples of 1950s batches appear to suggest otherwise.

However, it is conceded that SV40 was present in the early vaccine - and the latest research, published in the Lancet journal, has linked it to non-Hodgkin's lymphoma.

Opposition MPs demanded an inquiry last night into links between the Government and millionaire donor Paul Drayson's Powderject firm, amid accusations that Labour is giving preferential treatment to key financial backers of the party.

Drayson, who gave Labour £50,000, was at the centre of a contacts-for-cash row earlier this month after it emerged that Powderject won a lucrative government contract to make millions of doses of smallpox vaccine for use in case of a terrorist attack.

The deal was attacked by MPs from all parties who claimed it was not put out to proper competitive tender.

The Observer has learnt that as chairman of the Bioindustry Association, a trade body, Drayson led a lobbying campaign for special tax treatment for its members, including his own firm.

Drayson asked Ministers to allow the companies tax relief on everything they spend on research and development, which totals hundreds of million of pounds. According to an individual involved in the negotiations, some Treasury officials wanted to give relief only on spending above the present levels.

After a number of meetings between Drayson's association, the Treasury Minister Andrew Smith and officials, the Chancellor Gordon Brown chose the more generous option.

This will cost taxpayers £400m a year but boost the profits of Drayson's company - expected to be at least £10m next year - by more than £2m. The firm spends £30m a year on research, and its corporation tax bill will fall from £3m to £750,000.

The Cuban Health Ministry said a "rare accident" had occurred on 22 May after a group of schoolchildren were inoculated against the disease with apparently contaminated doses from India.

The vaccines were certified by the World Health Organisation and purchased through the Pan-American Health Organisation.

No details were given about who the victims were, or where the incident took place.

The Cuban authorities have halted the annual measles vaccination campaign while the causes of the deaths are investigated.

The investigation will be carried out by a specially set up ministerial commission.

Immunisation

Measles was eradicated from Cuba in 1993, but campaigns to immunise young children are regularly carried out.

In 2002, some 750,000 Cuban children between the ages of four and nine have already been vaccinated.

The Health Ministry note ends by saying no new problems have been reported in the week since the incident.

Some experts believe that these Trivax vaccines - which had not passed critical company safety tests - may have caused permanent brain damage and even fatalities in young children.

In 1992, the family of an Irish boy, Kenneth Best, who suffered brain damage from one of these toxic vaccines, was awarded £2.7 million in compensation by the Irish Supreme Court.

Despite a long and fierce battle with the drug giant, the boy's family finally won this historic case after his mother Margaret made a startling find when sifting through tens of thousands of company documents.

She discovered that the Trivax vaccine used on her son, from a batch numbered 3,741, had been released by the company despite it having failed to pass a critical safety test. Documents revealed that the 60,000 individual doses within this batch were known to be 14 times more potent than normal.

At the time the Irish judge accused GlaxoSmithKline - then known as Glaxo Wellcome - of negligence and attacked the company's poor quality control at its Kent laboratory. Immunology experts condemned Glaxo in court for what one US scientist described as an 'extraordinary event'.

Last year an investigation by The Observer found evidence to suggest that vaccines from this faulty batch, which may have wrecked Kenneth Best's life, had also been used in Britain.

An immunisation programme was launched last month by the United Nations in the northern city of Kano in an attempt to wipe out the disease.

But some Islamic preachers say they have strong reservations after the failure of a drug trial which they say killed a dozen children and left 200 others brain damaged six years ago.

The World Health Organisation (WHO) says it is using safe, licensed products, but stresses that it will not administer a medicine without consent.

Suspicions

The WHO campaign aims to eliminate the crippling disease in Nigeria by the end of the year, and in the other nine countries where it is found by 2005.

Health officials believe this is feasible after a coordinated 14-year global campaign brought down cases across the world by 99.8%, from 350,000 in 1988, to 600 in 2001.

But some Muslim clerics are not convinced and have discouraged people from having their children vaccinated.

When Edward Jenner tested his experimental vaccine against smallpox in 1796, he scraped the oozing pustule of a calf infected with cowpox and used a knife to press it into the skin of a small boy.
 
Today's vaccine is not much more advanced, although the boy escaped smallpox infection and the modern vaccine eradicated the disease.

But a vaccine that uses a live virus is harder to control, and this is the problem that U.S. health officials are struggling with in trying to decide who to vaccinate against smallpox.

Smallpox was declared eradicated in 1980, but the United States is worried that the virus may be used in a biological attack. The U.S. government is working to "stretch out" existing supplies of vaccine by diluting it and has ordered millions of new doses.

Routine vaccination stopped in the 1970s, so there has been no incentive to update the old tried-and-true vaccine to modern standards.

It is made from the lymph of heifers infected with cowpox -- a virus so closely related to smallpox that the body uses the same defenses for both. A person who has been infected with cowpox, a usually benign virus, is immune to smallpox.

The lymph in the vaccine is literally scraped from the pustules that cowpox causes in a calf.

The government is secretly considering buying another 20m doses of smallpox vaccine to protect more of the British population from a biological attack, the Guardian has established.

This time it is hoping to avoid accusations of sleaze - companies may be allowed to submit bids, according to industry sources, in a tacit admission that ministers made a mistake earlier this year when they agreed to pay £32m to a major Labour donor's company for vaccines rather than introducing a bidding process.

It was claimed at the time that UK, fearful of terrorist attack, had no alternative but to buy from Paul Drayson's firm Powderject, after he tied up a lucrative exclusive deal with the only Danish manufacturer of the specified strain.

Dr Drayson had donated £100,000 to Labour in the past year, £50,000 of it in January, at a time when ministers and officials were deciding who should be given the contract.

Powderject is making up to £20m profit after buying the drug supplies from the Bavarian Nordic company of Copenhagen for £10m.

But the Guardian has discovered that the Dutch ministry of health offered to supply the Lister strain vaccine more cheaply and as quickly, saving millions of taxpayers' money. It has already produced 20m doses for the Netherlands.

Like many parents, Catherine Sutcliffe did not hesitate when she was told by her doctor that her 14-month-old son Joshua should receive the MMR jab.

But the 36-year-old Halifax classroom assistant and her husband Mark, an IT consultant, say Joshua was never the same again after the jab in 1992.

Mrs Sutcliffe said: "He stopped being the child he was. He began rocking backwards and forwards, he stopped eating and put his fingers in his ears. He became autistic."

Four other children inoculated with the same batch of vaccine are autistic. Mrs Sutcliffe last year launched legal proceedings against one manufacturer of MMR, after the brand was withdrawn.

Anew report on millions of smallpox vaccinations given in the 1960's confirms that there is a small but significant risk that newly vaccinated people can make others seriously ill by infecting them with vaccinia, the virus used in the vaccine.

Scientists said the findings were reassuring, since the risk was so small — a few cases for every 100,000 vaccinations — but cautioned that the risk today might be higher than in the past, because more people have disorders of the skin or immune system that predispose them to adverse effects from the vaccine or close contact with those who have been vaccinated.

Smallpox vaccine has long been regarded as the most dangerous of all vaccines, both to recipients and their close contacts. For every million recipients, 15 will have life-threatening reactions, including 1 or 2 deaths, and hundreds will have severe rashes or other illnesses.

The risk to those who are unvaccinated but are in contact with those who are occurs because vaccinia, a relative of smallpox, is shed from the vaccination site for about three weeks and can make some people very sick. But the degree of risk to unvaccinated people has not been clear.

An author of the report, Dr. John M. Neff, a professor of pediatrics at the University of Washington, said the risk from vaccination or contact was "small, and it is significant."

"It is significant," he said, "because some of these adverse effects can lead to death. And it is significant because if you have a death or just one really serious adverse effect and the vaccination efforts were ill advised, you bear a heavy burden of responsibility, and it becomes very tragic."

The recent backroom political maneuver that gave Eli Lilly protection against lawsuits for damage allegedly caused by a mercury-containing preservative in vaccines was not only an abuse of Congressional process. Its more pernicious effect was to fan fears about the safety of vaccines and the ingredients used to protect them from dangerous contamination.

The preservative in question, known as thimerosal, was used in many vaccines to prevent microbial contamination until concerns were raised in 1999 that cumulative doses of mercury might cause subtle harm to the developing brain. Since then, thimerosal has been dropped from the vaccines routinely administered to infants in America, but the issue remains important because thousands of parents whose children had previously received mercury-containing vaccines have filed damage claims or lawsuits alleging harm.

Although mercury is known to be toxic at high doses, there is very little data on whether very low doses of ethyl mercury, the form found in thimerosal, can be harmful. Last year the Institute of Medicine, an arm of the National Academy of Sciences, concluded that the scientific evidence neither proved nor disproved a link between thimerosal and neurodevelopmental disorders in children. But this year the World Health Organization endorsed the preservative for global use, concluding that there is no evidence of toxicity in infants, children or adults exposed to thimerosal in vaccines. That judgment was buttressed by an encouraging study published last Saturday in The Lancet, a British medical journal. It found that vaccines containing thimerosal did not raise the amount of mercury in infants above federal safety limits and that the mercury was excreted quickly, suggesting that it would not accumulate with repeated vaccine injections and cause damage.