The population of the US is not vaccinated but many immigrants who enter the US do have a BCG vaccination. These people are also at the lower end of the economy are are susceptible to latent TB being activated.
In my research I did find a paper that questioned the effectiveness of the proteins being used in QF-1. Moreover, there needed to be a powerful impetus to change from the established skin test. I was not fully convinced that QF-1 had the muscle to drive the change.
On the other hand the link to SSI has resulted in QF-Gold which does satisfy my criteria. It also extends the patents [courtesy of SSI]. This removes the risk of a generic test after only several years of marketing QF-1 by CST.
QF-Gold has technical and commercial advantages that puts QF-1 in the shade. The wait may be longer but the benefits are greater.
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