Mystery surrounds secret 1991 vaccines

Britain sent more than 53,000 troops to the Gulf war 12 years ago. They faced the threat of chemical and biological attacks and a series of medical counter measures were hurredly introduced. The range of vaccines was kept secret, even from the troops, to prevent the Iraqis learning how they were protected.

But with the politcal furore over Gulf war syndrome, the Ministry of Defence published the full details - six years after the war - and admitted there were "significant deficiencies" in the programme.

Each individual was given up to 12 vaccines. First there were the routine ones to prevent disease: yellow fever, hepatitis B, typhoid, tetanus, cholera and polio. Some received jabs for meningitis and hepatitis A.

Then there were the anti-biological vaccines for anthrax and plague. The anthrax jab was given with one for pertussis (whooping cough) to make it work quicker, although this combination had never been tested on humans. Warnings about the risk from the Department of Health and the National Institute for Biological Standards and control were ingnored. After the war, research at Porton Down, the government's defence laboratory, concluded that the use of pertussis was ineffective.

For protection against a chemical attack everyone took a tablet containing the drug pyridostigmine bromide, which some scientists now believe may have been a contributory cause of neurological problems in veterans.

The troops were also exposed to potentially hazardous organophosphate pesticides, one of which was unauthorised and other, unidentified, ones were bought locally.

When veterans first started complaining of ill health, the most predominant symptoms were similar to those for chronic fatigue. Others included: headaches, memory loss, muscle pain, nausea, gastrointestinal problems, loss of concentration, vision and balance problems and depression. It has been established that veterans deployed to the Gulf are two to three times more likely to report symptoms than those not deployed.

Dozens of research experiments have been carried out since the late 1990s with the UK spending £8.5m and the US $213m (£133m). No conclusive results have been made but the early UK concentration on whether post-traumatic stress caused the illnesses has now largely been ruled out.