Plague vaccine will be licensed within two years, says UK team
in the development of an improved vaccine against plague, which
wiped out a third of Europe's population in the 14th Century and
has emerged more recently as a possible bioterrorist weapon.
Bubonic plague - the infamous 'black death' - is an acute infectious fever characterised by chills, prostration, delirium and swollen glands in the armpit or groin, and is caused by the bacterium Yersinia pestis. It is usually carried in rodents and transmitted to humans by fleas.
Up to 2,500 cases of the disease are diagnosed each year around the world and can be treated with antibiotics, although it is fatal in 60 per cent of cases if left untreated. However, plague is contagious - unlike botulinum and anthrax for example - and has a fearsome reputation which makes it important to have a vaccine not only to limit its spread, but also to quell public anxiety.
Researchers at the UK Defence Science and Technology Laboratory in Porton Down have successfully tested a candidate vaccine for safety in Phase II studies, and believe it could be ready for licensing within one to two years.
The researchers, led by Professor Rick Titball, designed the subunit vaccine after identifying two proteins on the surface of plague bacteria - known as F1 and V - which were capable of triggering an immune response against the disease.
Scientists at Porton Down have been working on a vaccine for plague since the 1991 Gulf War, when it was alleged that Iraq had been developing stocks of chemical and biological weapons including plague, anthrax and botulinum toxin.
An old whole cell vaccine for the disease does exist, but has been reserved for use in high-risk cases - such as those working in plague research - and the hope is that the new subunit vaccine will prove to be far more effective. A similar subunit vaccine, developed at the US Army Medical Research Institute of Infectious Diseases, is at a slightly earlier stage of development.
Researchers at Porton Down are also looking into the possibility of using Y pestis DNA as the basis of a vaccine. The group was involved in the sequencing of the plague bacterium genome in collaboration with the UK's Wellcome Sanger Institute.
