Caution on Smallpox Treatment

Analysis: There was lots of enthusiasm Monday on the NASDAQ for shares of Siga Technologies, a New York-and-Oregon-based biotech that's working on a possible treatment--as opposed to vaccine--for smallpox. But the rush of positive feeling is premature. The biodefense market may be hot, but there are plenty of caveats in this story.

So why did Siga close at $5.15 a share, up 14% yesterday? A toddler from Indiana became very ill with a life-threatening rash that covered most of his body after his soldier-father was vaccinated for smallpox.

Now the smallpox vaccine is based on a weakened strain of a related virus, called vaccinia, that can cause its own problems. Although vaccinia disease is usually much milder than smallpox, vaccinia can and does kill. In this case, the child caught the vaccinia infection from his father. (Let's be absolutely clear here: the child has vaccinia disease, not smallpox.)

Doctors gave the boy an experimental anti-smallpox drug (ST-246) being developed by Siga Technologies in the hopes that it would help him recover from the vaccinia infection--and preliminary results are encouraging. But the boy is still in critical condition, according to Reuters.

So next things to watch for: How well does the boy recover? How soon after exposure will such anti-viral drugs, if developed, have to be given? How can they be tested since smallpox has been eradicated and the threat is still from accidental or malevolent release? What kinds of scale-up and distribution problems will there be for a drug treatment for smallpox--which we hopefully will never need? Why wouldn't an updated, safer smallpox vaccine be better than any potential drug treatment?