In the event of contact with a person with contagious tuberculosis, the intensity and duration of the contact are decisive for the possible risk of infection. Tuberculosis is less easily transmitted than other aerosol-borne diseases and not all people with tuberculosis are contagious. The responsible health authority can offer advice. If contact with a person with infectious pulmonary tuberculosis is considered relevant, further investigations will be initiated.

The public health department usually carries out a so-called environmental investigation for every infectious case of tuberculosis. In order to find all persons with a risk of infection, all contact persons should be identified. Here too, the public health department decides whether further tests are advisable depending on the type and duration of contact.