Re: Is there still a chance for us?

Date: Tue Sep 25 2001 - 11:34:49 MDT

In a message dated 9/24/01 1:23:54 PM, writes:

>Does anyone know whether the protection from childhood vaccination
>would help against the use of smallpox as a terrorist agent? Is there
>some technology to mutate the virus so that the vaccines don't work?

Theoretically you could engineer the virus to alter its antigenicity.
You'd have to alter most of the proteins in the virus. With something
as big as smallpox, that would be phenomenally difficult. A chimeric
virus is a little more plausible but still a big research project, and
if the chimera had the transmission properties of smallpox it would
likely share most of the antigenicity too. So the vaccines will work
for some time against plausible release threats.

>One would think that smallpox would not be the biological weapon of choice
>against a population where perhaps half the people had been vaccinated
>against it.

The high immunization is a strike against it, but otherwise smallpox is
almost a perfect biowarfare terror weapon. Tolerates drying, ferociously
contagious, airborne, substantial latency (several days, IIRC), and
it's easy to immunize your own population.

>The smallpox vaccine is based on the vaccinia virus (which is where
>the name "vaccine" comes from), so I don't fully understand why
>concerns about smallpox virus availability required withdrawing
>the vaccinia-based vaccine.

Just speculating, but consider how the USSR would have felt about
a US smallpox vaccination campaign after it had been eradicated from
the wild. Turn it on its head and imagine how you'd have felt in
1989 if you'd found out the Soviets were immunizing their entire
population against smallpox.

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