We had a case at school not that long ago. All students in the year group and staff who came into regular contact were given the TB skin test, plus the test was offered to any other member of staff who wanted it. If the skin test was positive you got sent to the hospital for a chest x-ray. Turned out 1 other student had TB and they were put on medication. Since then there have been no further cases. TB isn't very contagious, you need to be in close contact for long period of time to contract it.