Should stocks of smallpox virus be destroyed?

Smallpox was eradicated in 1980, but the virus still exists in WHO controlled depositories. In this week's British Medical Journal, two experts go head to head over whether these stocks should be destroyed.

The destruction of remaining smallpox virus stocks is an overdue step forward for public health and security that will dramatically reduce the possibility that this scourge will kill again, either by accident or design, argues Edward Hammond of The Sunshine Project, an organisation seeking international consensus against biological weapons.

In 1999 Russia and the US balked at the World Health Assembly resolution calling on them to destroy the virus. Since then, both countries have accelerated smallpox research.

Particularly risky experiments are underway, he says, yet WHO experts have agreed that no valid reason exists to retain smallpox virus stocks for DNA sequencing, diagnostic tests, or vaccine development.

Arguments that smallpox could be used by terrorists or “rogue states” have also been used to justify retention of virus stocks, yet there is no credible evidence that any terrorist organisation has smallpox virus, says Hammond. He also points out that to acquire the virus, terrorists would have to breach security at one of WHO's repositories, and that producing quantities of weaponised smallpox is beyond the means of any known terrorist group.

As memory of the horror of smallpox recedes and biotechnology advances, it is important to draw a firm line around smallpox, he writes. “Instead of courting disaster, we should seek to ensure that possession of this virus is treated as a crime against humanity.”

But John Agwunobi of the US Department of Health and Human Services believes that clandestine stocks almost certainly exist and that destroying the virus would be “irreversible and short sighted.”

He disagrees with the view that live smallpox virus is no longer needed for research purposes and insists that further study is essential for global security. He points out that we currently have no effective antiviral drugs for smallpox infection.

The development and licensure of better diagnostics, safe and effective drugs, and safer vaccines against smallpox will take time, he writes. Setting an arbitrary date to complete scientific research is premature and short sighted.

As long as there is a possibility that terrorists could use smallpox to wreak havoc, WHO supervised research must continue so scientists can develop the tools needed to combat an outbreak of smallpox effectively and efficiently, he concludes.

Even if smallpox were to be introduced into the population, the number of cases is unlikely to be large, adds Tom Mack, Professor of Preventive Medicine at the University of Southern California in an accompanying editorial.

He warns that other viruses pose greater public health threats. For example, release of the highly virulent recombinant 1918 influenza virus would be a real catastrophe, he says, yet retention and distribution of recombinant strains for study is enthusiastically justified on the basis of the need for effective protection, diagnosis, and treatment.