How dangerous an escape from the lab?

[wevets]

What are the chances that small pox would escape from the labs that contain the remaining samples?

I saw this:

The two main arguments against destruction of the virus are that it will eliminate the possibility of future studies on the virus and that destruction of the virus in the two known repositories may not guarantee complete eradication (81-83). The main arguments for destruction are that escape of the virus from the laboratories would be a serious risk because an increasing proportion of the global population lacks immunity to the disease and that the sequence information and the availability of cloned DNA fragments of the full genome of several strains of the virus will allow most scientific questions about the properties of the viral genes and proteins to be resolved.

From the Annals of Internal Medicine (http://38.232.17.254/journals/annals/15oct97/smallpox.htm)

So I was curious about how large the risk of escape is.

[melchizedek]

I remember hearing on the news, some 20 or so years ago about a nurse in Birmingham UK somehow contracted Smallpox from a culture kept in a lab.

I guess there is a contingency plan to prevent widespread outbreaks, as I never heard any more about it and can't remember what happened, whether anyone else caught it or whether she died.

[Smeghead]

Well, at least in the US, the remaining specimens (in the CDC) are under pretty tight lock and key. So if you're asking how likely accidental release is, I'd say not very. If you're wondering about deliberate release, the question then becomes, "How dedicated are terrorists?", on which I am not qualified to comment.

And if you're wondering about workers getting accidentally infected and spreading it, there are measures to prevent that, too. Anyone working with dangerous pathogens routinely undergo serological tests to check for accidental exposure. It would be detected quickly and brought under control.

[Alphagene]

Also, AFAIK, people who work with smallpox are generally immunized against it.

A smallpox vaccine supply exists today but it is a very small amount. Apparently, the supply is so low that people working with smallpox are being immunized with diluted vaccine in an attempt to conserve what is left.

The biopharmaceutical company Acambis (formerly known as OraVax) was given several hundred million dollars by the CDC in September to make 40 million doses of smallpox vaccine (http://biz.yahoo.com/prnews/000920/ma_oravax_.html) by the year 2004.
The CDC plans to hold the new vaccine in reserve, to only be used for the control of smallpox in the event of a confirmed case of smallpox infection. The vaccine may however be used in laboratory workers directly handling vaccinia or related poxviruses.