Because the incidence of tuberculous infection cannot usually be measured, the average annual risk of tuberculous infection is calculated from a tuberculin skin test prevalence survey.  If several surveys are available for a population, then trends in the risk of infection can be evaluated and predictions about the likely future course can be made.

Estimates of the risk of infection have also been used to estimate the number of infectious sources that cause this risk of infection in the community.  The problems with this approach will be discussed in the second part of this block.

To top