vaccine for tb, page-5

G'day kist,

Gee, after weeks of nothing, suddenly I'm having a busy CST day. :) Still, always good to welcome another sucker (oops investor) on board.

The particular test that you mention, Vscan, and many others, is a test for ACTIVE TB only. There is a place for this type of test but it does not impinge on CST's market at all. Quantiferon-Gold from CST tests for both LATENT and ACTIVE TB.

The difference between the two is a bit of a long story but I'll try to explain it briefly. You can "catch" TB off somebody that has active TB. Active TB sufferers have a nasty cough and often cough up blood. If left untreated they will most likely die. If you catch TB then if your immune system is in good condtition it will fight and contain (but not eradicate) the TB bacterium. (It sort of builds a wall around it). In this state you are said to have latent TB. If, at some later date, your immune system becomes weakened (many things can do this, including HIV, age, other medical treatments etc etc), then the latent TB will "break out" and will become active. Overall, the lifetime risk of your latent Tb becoming active is between 10% and 15%.

Okay, so to immediately stop people dieing it is important to treat those with active TB. But if you want to eradicate TB from the community you must identify and treat those with latent TB. Otherwise some of those people will become active and start the cycle again. The antibiotics to treat latent TB are not terribly expensive (as low as $US10 in the developing world).

Currently, the only test available for detecting latent TB is the TST test (skin test or Mantoux or Heaf). This test has numerous failings. It is inaccurate, clumsy and nasty.

This is where Quantiferon-Gold comes in. It is an elegant blood test for TB (both latent and active). It has a particularly high sensitivity and specifity.

There is heaps more to the story and if you want to chat to a bunch of folk who are particularly well informed then you may wish to check out the CST board on Ozestock. (it's okay ... Ozestock is a cousin of HotCopper).

Now, to your final question. "Are CST likely to get FDA approval". The answer to that question is an almost definate YES. The only question that remains unanswered is WHEN. In truth, nobody knows the exact answer to this but, having mulled it over and discussed it till the cows come home with others, it is my feeling that it will happen within the next few weeks. We do know that all data has been submitted to the FDA and all 100day questions have been answered. This approval is what is known a a 180day supplement and all calculations indicate that it should be any day now.

I hope this is of help, kist.