Thursday, September 10, 2009

Diluting the Smallpox Vaccine

Considering this was such a big issue in our 'atlantic storm' simulation, I thought it would be appropriate to investigate the study. It turns out that it is possible to dilute the vaccine by a ration of 10:1 and still record just as high a percentage of 'takes'. Guess the Prime Minister of England was a bit ignorant of the facts.....

In March 2002 HHS Secretary Tommy G Thompson announced that the exisiting U.S. supply of smallpox vaccine -15.4 million doses could successfully be diluted over five times and retain its potency, expanding the number of individuals it could protect from the contagious disease.

The trial compared the full strength vaccine with fivefold, as well as tenfold, dilutions in 680 young adults with no history of smallpox vaccination. 97% of all participants registered a take.

Participants were assigned at random to one of three groups: 106 received undiluted vaccine, 234 recieved a 1:5 dilution, and 340 received a 1:10 dilution.

After one or two vaccinations, the investigators found no significant difference in the take rate of the three doses: 97 percent of volunteers who received undiluted vaccine had a take compared with 100 percent of those receiving the 1:5 dilution and 98 percent of those receiving the 1:10 dilution.

So perhaps we should have diluted the vaccine, although it has never been tested via the Jenner Method. A take may not necessarily mean long term protection against smallpox

Matthew Goodyear

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