Smallpox Stockpiles Avoid Chopping Block… Again

By Chris Healey

Last month, World Health Organization officials at the 106th World Health Assembly in Geneva decided not to eliminate the last stockpiles of smallpox. That decision marks the sixth time the assembly has chosen to maintain stockpiles in lieu of destruction.

Some health officials consider smallpox the deadliest disease in human history. Until vaccination eradicated the disease in 1980, smallpox infected people around the world and killed 30% of sickened individuals. The disease no longer exists in nature, but samples of the virus are stockpiled at research facilities in the United States and Russia. Elimination of those stockpiles is the only way to categorically prevent theft or accidental release of smallpox from those facilities.

One source of hesitance to eliminate is international intrigue. In 2008, representatives from Vector, the Russian facility responsible for the country’s stockpile in Novosibirsk, announced researchers had discarded 200 smallpox samples without notice. Elimination of those samples remains unverified.

Another reason to keep stockpiles is research potential. Access to samples in the event of a smallpox resurgence, or another poxvirus outbreak, may be beneficial in efforts to quell illness spread. Most poxviruses have strikingly similar genomes.

Smallpox is part of the orthopox genus. A characteristic of orthopox genomes is conservation of genetic material, meaning viruses in the genus share many identical genetic sequences.

Genetic similarity among viruses in the orthopox genus is exploited to prevent smallpox. Vaccinia virus,the pharmacologic active ingredient in smallpox vaccines, shares enough genetic similarity with variola virus, the causative agent of smallpox, to confer immunity to both viruses. In fact, inoculation with any orthopoxvirus confers immunity to all members of the genus.

Some health officials claim the conserved nature of orthopoxviruses undermines needs to preserve smallpox. Due to similarity among orthopoxviruses, smallpox can be studied through less virulent orthopoxviruses. However, not all health officials believe orthopoxviruses are one in the same.

Authors of an article recently published in The Lancet make an argument for the preservation of smallpox stockpiles. The authors mention the need for better countermeasures against smallpox and other orthopoxviruses. Those countermeasures, when developed, should be tested against authentic smallpox viruses. The authors argue smallpox stockpiles should be maintained to facilitate orthopoxvirus research.

A comprehensive review of the smallpox stockpile elimination debate by biological weapons and arms control expert Jonathan Tucker is available here.

2 thoughts on “Smallpox Stockpiles Avoid Chopping Block… Again

  1. The very fact that the variola virus is more virulent than vaccinia in humans is surely enough reason to suggest that there are important differences between the two. I’m not necessarily advocating the continued maintenance of the stockpiles, but I don’t think that it can be argued that studying vaccinia is a complete proxy for variola.


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