A vaccine for the bubonic plague, which killed millions in the Middle Ages and is now one of the deadliest bio-terrorism agents, may be available within a year as a result of a breakthrough at the Ministry of Defence’s laboratory at Porton Down.

Initial clinical tests on human beings at the laboratory in Wiltshire have produced no adverse side-effects, clearing the way for large-scale trials.

Rick Titball, group leader for microbiology at Porton Down, told The Times yesterday that the vaccine could be licensed “within a year or two”.

Professor Titball said it represented one of the biggest achievements at Porton Down in the past ten years.

The results of the large-scale clinical trials are expected to be published in a scientific journal in about a year.

He added: “The Americans are very keen on our programme because we are well in advance of any other research projects developing a vaccine elsewhere in the world.”

There is an existing vaccine in Australia but Professor Titball said it “was not particularly effective”. An American version based on the same principle as the Australian one was abandoned in 1999.

Professor Titball said the Porton Down vaccine had been developed in a comparatively short time. The clinical trials would be “relatively expensive”, he said, because of the number of volunteers involved.

Scientists at Porton Down have been working on a vaccine since the 1991 Gulf War when it became apparent that Iraq had been developing huge stocks of chemical and biological warfare agents, including bubonic plague, anthrax and botulinum toxin.

Although there was a licensed vaccine for anthrax that was given to British troops for the 1991 Gulf War and made available for the war in Iraq last year, the development of a plague vaccine was not sufficiently advanced to add to the list of inoculations.

Now, with the fear that an international terrorist organisation such as al-Qaeda might turn to non-conventional forms of attack, using chemical, biological or radiological devices, the work at Porton Down has taken on even greater significance.

Professor Titball, who has worked at Porton Down for more than 20 years, said it was possible that a terrorist with a degree in microbiology would be capable of constructing a device using plague bacteria.

Although he would not say whether plague was considered to be potentially the biggest killer in the hands of a terrorist, he acknowledged that it was “one of the bio-terror agents about which we are most concerned”.

He said that in the next stage of the plague vaccine programme several thousand volunteers would be used in full clinical trials.

He expected that there would be no difficulty in finding enough volunteers “because we have already shown that this is a safe vaccine with no adverse side-effects”.

Professor Titball’s colleague at Porton Down, Jill Cook, is the project manager for the plague vaccine programme. But it was a team led by Professor Titball that made the original breakthrough discovery in developing a possible vaccine and published the findings in 1995.

He and his team identified two harmless proteins on the surface of plague bacteria which were capable of triggering an immune response against the disease.

He said: “These two proteins are key parts of the plague organism which are recognised by the immune system and respond to them.”

One of the problems for the Porton Down team was that bubonic plague is not prevalent as a disease on a large scale anywhere in the world. So it was not possible to carry out tests on thousands of people who might be vulnerable to the disease.

The World Health Organisation says there are about 2,500 cases of plague every year, scattered in different parts of the world. The disease is normally transmitted by fleas from rats and other rodents.

An outbreak of pneumonic plague — relating to the lungs — occurred in India in 1994, after an earthquake in Surat, 200 miles north of Bombay. Nearly 60 people died.

KILLER THROUGHOUT THE AGES

• The first known plague pandemic began in Egypt in 541 AD, killing about 50 per cent of the world population
• In the Great Plague of London in 1665, an estimated 100,000 people died
• Plague is caused by Yersinia pestis, a bacterium named after Alexandre Yersin, a Swiss scientist who identified the bacillus in the late 19th century
• A bubonic plague infection from flea bites takes two to eight days for symptoms to develop — fever, nausea, vomiting, diarrhoea and swollen lymph nodes that ooze blood

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