What is TB and how is it spread?
TB is caused by a bacterium called Mycobacterium tuberculosis. TB usually infects the lungs, but can infect any organ of the body. When TB infects the throat/lungs, it can be spread through the air from one person to another. TB bacteria become suspended in the air when someone with TB of the throat or lungs coughs, sneezes, speaks, or sings. People who share airspace with the infected person may breathe in these bacteria and become infected.
Usually a person has to be in close contact with someone with infectious tuberculosis for a long period of time to become infected; however, some people do become infected after short periods, especially if the contact is in a closed or poorly ventilated space. Not everyone infected with TB bacteria become sick. Those that don’t become sick have latent TB infection (LTBI), which is defined as a positive TB skin test or Quantiferon Gold test.
What is considered to be an exposure to TB?
A person is considered to be exposed if one or both of the below apply:
- Shared airspace with someone with pulmonary TB at a time when the infectious person is not wearing a mask and the employee is not wearing an N95 respirator.
- If employee is in a room of a known TB patient, without the patient present, the individual will be exposed if the patient was in the room less than one hour ago.
What is the incubation period for TB?
From infection to development of a positive TB skin test reaction (the incubation period) is approximately 2 to 10 weeks. The risk for developing active disease is the highest in the first two years after infection and development of a positive TB skin test reaction.
What should I do if I am exposed to a person with confirmed TB?
Notify your manager and Employee Health of your exposure.
- Employees with a previous negative TB skin test – baseline skin test placed immediately and at 8-10 weeks.
- Employees with a previous positive TB skin test - baseline questionnaire completed immediately and at 8-10 weeks to screen for active signs and symptoms of TB.
Can I spread this to others after exposure?
No, you have to be sick with active TB to transmit.
What do I do if I am pregnant when I am exposed?
There is no additional risk to you or your baby. Pregnant employees will follow the same post exposure protocol as a non-pregnant employee.
What if my tuberculin skin test is positive after I have been exposed to a known case of TB?
A TB skin test reaction of 5 mm induration or greater is considered positive. You will then be evaluated for signs and symptoms of active tuberculosis (cough lasting for more than three weeks, bloody sputum, fever, night sweats, weight loss, loss of appetite, fatigue).