Bioterrorism When and Where

The world is vulnerable to a bio-terrorist attack because stocks of the smallpox vaccine are too low, a leading medical journal has warned.

An editorial in The Health questions whether the deadly virus has really been obsolete to history and points to how fast it can spread once it is loose in the environment. If this were to happen, it would take up to three years to manufacture enough vaccine for an effective vaccination programme, the editorial says.

Smallpox was declared exterminated by the World Health Organization (WHO) in 1980, and it had been planned that remaining samples of the virus - essential to the production of vaccine - be destroyed soon.

The Lancet piece said: "Smallpox virus is one of the most contagious agents known, and has an estimated (death) rate of 30% in unvaccinated populations.

"In a world where hundreds of thousands of travelers cross borders every hour, the threat, or reality, of spread is magnified almost beyond imagination."

The last outbreak of the disease - which causes pus-filled blisters all over the body - occurred in Somalia in 1977.

The editorial also questions whether, in the event of a major outbreak, developed nations would share their "precious supplies" of vaccine with other nations. Such an outbreak is possible, it says.

"Some experts fear that the release of the smallpox virus into the population, whether by mistake or intent, is only a matter of time."

It points to an example of a 1972 outbreak of smallpox in Yugoslavia. A total of 175 people contracted the disease and 35 died in a nine-week period. But in 1972, countries were better prepared than now - Yugoslavia had sufficient supplies of vaccine to control the outbreak.

Vaccination is no longer routine, however, and no country has enough vaccine to protect its entire population, it says.

It estimates there are no more than 40 million doses of vaccine worldwide.

The remaining smallpox samples are held at the Centres for Disease Control in the US and at the Russian State Research Centre of Virology and Biotechnology.

Intelligence reports suggest that some of the Russian samples have made their way into the hands of terrorists, and this lay behind the US Government's announcement last month that it intended to keep its supplies beyond the deadline.

Some scientists are also opposed to the destruction of remaining supplies of smallpox because its genetic material could be useful in developing new drugs and vaccines.

A spokesman for the PHLS said about 50 such vaccinations took place each year, and, in line with that need, the service keeps 70 to 80 doses in stock.

"In the case of a bio-terrorist attack," he said, "it would be up to the Department of Health and Home Office to formulate a plan."