Tuberculosis is a bacterial infection mainly with symptoms from the lungs. Healthy people are not very susceptible to infection.
Vaccination is not to be recommended in connection with short trips, but it is to be recommended for people who are going to stay for long periods of time (more than six months) in Africa, Asia, South and Central America and who are going to have close contact with the local population.
The vaccine protects especially children against the serious kinds of tuberculosis, whereas its effectiveness in adults is questionable. Revaccination is not recommended.