Although smallpox by itself is problematic as an effective bioweapon, it has been shown that smallpox may be more useful as a delivery vehicle for a more deadly condition.

Australian scientists (Jackson, Ramsay, Christensen, Beaton, Hall, and Ramshaw, of the Pest Animal Control Cooperative Research Centre, CSIRO Sustainable Ecosystems, Canberra, Australia) have added a gene responsible for producing interleukin-4 to mousepox. 2 out of 4 mice that had been vaccinated against mousepox died. All mice not vaccinated died.

Presumably, this would work something like a fast-acting immunodeficiency virus. So I have affectionately dubbed such a theoretical smallpox modification "AIDSpox". Normal smallpox methods of preventing the spread of the disease (quarantine) would still apply, of course.

I've been asked to revise this for clarity, so here are relevant facts I have been asked for and quotes to supplement:

It turns out the vaccine was successful half the time, according to New Scientist, with the connotation that this was an optimistic figure if such an experiment were repeated. I don't remember where my 75% mortality came from. In the above, "2 out of 4" originally read "3 out of 4". Please pretend I didn't write it. We Apologize For The Inconvenience.

Further (emphasis is all mine):
The researchers were actually working on a mouse contraceptive vaccine for pest control, according to New Scientist today. But they started with a mousepox virus that normally made laboratory mice feel mildly ill. They inserted an extra gene, and ended up with a virus that wiped out all animals in nine days.1

Mousepox normally causes only mild symptoms in the type of mice used in the study, but with the IL-4 gene added it wiped out all the animals in nine days. "It would be safe to assume that if some idiot did put human IL-4 into human smallpox they'd increase the lethality quite dramatically," says Jackson. "Seeing the consequences of what happened in the mice, I wouldn't be the one who'd want to do the experiment."2

And my personal favorite:
It's surprising how very, very bad the virus is. - Ann Hill, a vaccine researcher from Oregon Health Sciences University in Portland.2




Jackson RJ, Ramsay AJ, Christensen CD, Beaton S, Hall DF and Ramshaw IA. (2001). Expression of mouse interleukin-4 by a recombinant ectromelia virus suppresses cytolytic lymphocyte responses and overcomes genetic resistance to mousepox. Journal of Virology 75: 1205-1210.