Original: About 90% of those infected with Mycobacterium tuberculosis have asymptomatic, latent TB infection (sometimes called LTBI), with only a 10% lifetime chance that a latent infection will progress to TB disease.
Simplified: If a person becomes infected with TB, there is a 90% chance that it will be a latent TB infection, meaning that they will not become sick or infect other people. However, there is a 10% chance that the latent TB infection will turn into Active Tuberculosis Disease at some time in the person's life.