The cumulative risk of developing tuberculosis subsequent to acquisition of tuberculous infection has often been quoted as approximately 10% for a person who has become infected as a young person. It is very difficult to estimate, because people cannot be followed up for their entire life.
This study, using a model based on data from England and Wales suggests that the lifetime risk of pulmonary tuberculosis is somewhere between 10% and 15%. As sputum smear-positive cases constitute some 60% of all pulmonary tuberculosis cases, the lifetime risk of developing this form was estimated to be somewhere between 5% and 10%.
