Should we deliberately make a living organism extinct? Some argue that we should, where that organism is a deadly virus that killed around 300 million people during the 20th Century, leaving many more scarred for life. The organism in question is the smallpox virus.

Smallpox is one of the few complete medical success stories, the only disease to have been totally eradicated in Nature. The last natural case occurred in 1977 in Somalia, after a long and intensive vaccination campaign that used 2.4 billion doses of vaccine.

But there was one more smallpox death in 1978, when a laboratory worker in Birmingham, England was accidently infected with virus stored there. Those stocks were destroyed, leaving only two secure reserves; one in Atlanta in the USA and one now in Siberia. But should these too now be destroyed?

Jon Stewart looks at the history of smallpox and discusses its possible future with Edward Hammond, consultant to The Third World Network NGO, who believes the virus should be destroyed; and Raymond Weinstein of Georgetown University School of Medicine who makes the case for preserving it in secure facilities for possible research to combat disease or bioterrorism.