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Logo of bmjThis ArticleThe BMJ
BMJ. 2007 April 14; 334(7597): 774.
PMCID: PMC1851992
Head to Head

Should the US and Russia destroy their stocks of smallpox virus?

Edward Hammond, director

Smallpox was eradicated in 1980, but the virus still exists in WHO controlled depositories. Edward Hammond maintains that stocks should be destroyed to prevent the disease re-emerging, but John Agwunobi insists further research is essential for global security

The World Health Organization is justly proud of the global effort that led to the eradication of smallpox; but the truth is that the job remains unfinished. Although it is almost 30 years since the last natural transmission of smallpox virus (Variola),1 laboratories in the United States and Russia retain virus stocks.

The destruction of remaining Variola stocks is an overdue step forward for global public health and security that will greatly reduce the possibility that this scourge will kill again, by accident or design. Although deploying modern scientific techniques such as genetic engineering on smallpox virus may be intellectually intriguing, the risks far outweigh the potential benefits.

In 1990, the US secretary of health and human services, Louis Sullivan, made a pledge on behalf of the US government. “There is no scientific reason not to destroy the remaining stocks of wild virus,” he declared, “So I am pleased to announce today that after we complete our sequencing of the smallpox genome, the United States will destroy all remaining virus stocks.”2 Although the genome was published in 1994,3 the US still hasn't honoured its commitment.

WHO member states concur that the virus stocks must be destroyed. For more than a decade, the US and Russia have paid lip service to the WHO consensus while trying to outmanoeuvre actual destruction of the virus. In 1999 Russia and the US balked at the World Health Assembly resolution calling on them to destroy the virus (resolution 49.10). Since then, both countries have accelerated smallpox research. Particularly risky experiments are underway to create a monkey model of human smallpox infection.4 The US has also proposed genetic engineering experiments with the virus.5

WHO's experts have agreed that no valid reason exists to retain smallpox virus stocks for DNA sequencing, diagnostic tests, or vaccine development.6 In 2006, WHO's experts concluded: “Sufficient sequence information on the virus was now available; no further research requiring access to live variola virus was considered essential.” They also determined that “the number of detection and diagnostic systems for variola virus now available was adequate.”6 Antivirals are not absolutely required because existing vaccines are effective and diagnostic tests are rapid and accurate. And WHO experts have recently suggested that drugs against smallpox could be developed without the dangerous US experiments with live smallpox virus intended to create an animal model of human infection. WHO advisers suggest that this could be accomplished through the far safer route of using monkeypox virus.7

Questionable threat

The US has recently made much of the possibility of smallpox in the hands of terrorists or “rogue states.” Illicit stocks have been used to justify retention of US and Russian smallpox virus stocks. There is a fallacy lurking here because smallpox virus stocks are not necessary to respond to a smallpox outbreak. If smallpox reappeared, the virus would be readily available if needed for biomedical purposes.

The claims about illicit stocks have also not been supported by evidence. The loudest allegations were against Iraq, but the US belatedly admitted that it was wrong. There is no credible evidence that any terrorist organisation has smallpox virus. To acquire the virus terrorists would have to breach security at one of WHO's repositories. Producing quantities of weaponised smallpox is beyond the means of any known terrorist group.

Increasing danger

The US National Science Advisory Board on Biosecurity is currently discussing a proposal to weaken domestic legislation to permit US laboratories to synthesise and possess larger sequences of smallpox DNA.8 This will make its DNA easier to acquire and increase the range of dangerous experiments possible outside the official WHO virus repositories.

In 2005, the head of the WHO eradication effort, Donald Henderson, told the Independent: “The less we do with the smallpox virus and the less we do in the way of manipulation at this point I think the better off we are.”9 Yet one unfortunate consequence of the US insistence that its smallpox virus is critical to its national security is that other countries may become convinced that they too must possess the virus and research into it. The smallpox strains in the WHO repositories in the US and Russia were deposited by various countries and were isolated all over the world. It is extremely unclear who legally owns the collections.

The decades old eradication job of WHO will be completed, and the world will be safer, when the US and Russian smallpox virus stocks are finally destroyed. Recently, Africa has taken the lead at the World Health Assembly. Its health ministers see all too clearly what could happen if smallpox were to escape. Africa's efforts, with support from other developing regions, have put WHO member states into a position to do more than recall unfulfilled pledges when the World Health Assembly convenes in May 2007.

As memory of the horror of smallpox recedes and biotechnology advances, it is important to draw a firm line around Variola. Instead of courting disaster, we should seek to ensure that possession of this virus is treated as a crime against humanity. The key prerequisite to criminalising Variola is to destroy the existing stocks. It has been three decades coming, but it is time for WHO to push the button on the autoclave. Better late than too late.


Competing interests: The Sunshine Project campaigns against the hostile use of biotechnology.


1. World Health Organization. Smallpox surveillance. Wkly Epidemiol Rec 1977;52:389-91.
2. Mahy BWJ, Esposito JJ, Venter JC. Sequencing the smallpox virus genome. ASM News 1991;57:577-80.
3. Massung RF, Liu LI, Qi J, Knight JC, Yuran TE, Kerlavage AR, et al. Analysis of the complete genome of smallpox variola major virus strain Bangladesh-1975. Virology 1994;201:215-40. [PubMed]
4. Jahrling PB, Hensley LE, Martinez MJ, Leduc JW, Rubins KH, Relman DA, et al. Exploring the potential of variola virus infection of cynomolgus macaques as a model for human smallpox. Proc Natl Acad Sci USA 2004;101:15196-200. [PubMed]
5. WHO Advisory Committee on Variola Virus Research. Report of the sixth meeting, 4-5 November 2004
6. WHO Advisory Committee on Variola Virus Research. Report of the seventh meeting, 10-11 November 2005
7. WHO. Smallpox eradication: destruction of variola virus stocks. May 2006.
8. National Science Advisory Board for Biosecurity. Meeting archives, 13 July 2006
9. Connor S. Outcry over creation of GM smallpox virus. Independent 2005 Jan 22.

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