Why have we contacted you?
You have been identified as being in contact with a person who has infectious TB. We recommend you are tested to see whether you have been infected with TB. Depending on your results, we may recommend treatment or further follow-up.
What is TB?
Active TB disease is caused by infection with the bacteria Mycobacterium tuberculosis and is curable with antibiotics. TB usually affects the lungs, but can sometimes affect other parts of the body, such as the lymph nodes, kidneys, and bones. TB infection usually doesn't have any signs or symptoms and in most cases the TB germs are not active – this is referred to as dormant or latent TB infection. A person with latent TB infection is not infectious and cannot pass the germs on to family or other close contacts.
I don't know anyone with TB - how could I be infected?
As TB spreads through the air you may not know the person who may have exposed you to TB. To protect patient privacy, we can’t tell you who the person is, nor where the exposure may have occurred.
How do people become infected with TB?
TB germs are spread through the air when someone with TB disease in their lungs or throat coughs, sneezes, sings or speaks, sending small droplets into the air. These droplets can be breathed in by other people. Most people get TB from someone they spend a lot of time with. It is very unusual to get TB from someone after brief or casual contact. TB is not spread by household items such as cutlery and crockery, or telephones.
I don't feel sick - how can I tell if I have been infected?
TB infection does not cause any symptoms, so we have to use special tests to diagnose TB infection.
Tests can be done at or coordinated through your local TB Service. These tests include:
- A blood test called an interferon gamma release assay (IGRA or QuantiFERON TB Gold Plus®) can show whether you are have been infected with TB.
- A tuberculin skin test (also known as a TST or Mantoux test) is a small injection given just under the skin on the inside of the forearm. You will need to return 2 to 3 days after the test has been given so that any reaction (swelling & redness) to indicate TB infection can be assessed.
- A chest x-ray can show whether there is any TB in your lungs. Sometimes a chest x-ray will show signs of past TB, even if you are not aware of having had TB previously.
I have had a TB vaccination (Bacillus Calmette-Guerin or BCG). Doesn’t this protect me?
The BCG vaccine works best to prevent serious forms of TB in children under 5 years of age, however it does not prevent TB in all cases. You can get TB disease even if you have had a BCG vaccination.
What happens if my tests are negative?
If your first blood test or tuberculin skin test is negative, the test may be repeated in 2 to 3 months. This is because it can take several weeks after exposure to TB for your immune system to react. Therefore, if a second test is recommended it is very important that you come for this test to ensure that you are clear of TB infection. If your second test is negative, you will not require any further tests.
What happens if my blood test or skin test is positive?
If your test is positive, you will be requested to have a chest x-ray, and depending on your chest x-ray result and other risk factors you may be referred to a specialist TB doctor.
Having a positive test does not necessarily mean that you have been infected as a result of your recent contact with a person who has TB. If you have lived in a country where TB is common, then there is a good chance that you may have had the infection for some time. Approximately one quarter of the world’s population have latent TB infection, though it is rare among people who are born and have only lived in Australia. Sometimes, a positive tuberculin skin test occurs in people who have had a BCG vaccination or for other reasons not related to having TB infection.
Having latent TB infection does not mean that you have active TB disease or are infectious. However, it does mean that you have some risk of developing active TB disease during your life. How big this risk is depends on many factors, including how recently you became infected (recent infection is higher risk), how old you are, and whether or not you have some medical conditions. The nurse or doctor will discuss this further with you.
Can latent TB infection be treated?
Latent TB infection can be treated to help prevent the development of TB disease in the future. This treatment generally involves taking one or two of the drugs that we use to treat people with TB disease for three to nine months. The treatment is effective in preventing TB disease in most people who have latent TB infection. This treatment is generally safe, particularly in young people. If your doctor recommends this treatment, he/she will tell you more about the benefits and any potential side effects.
Is there any alternative to taking treatment if I have latent TB infection?
Yes. If your risk of developing TB disease is low, then your doctor may recommend a “wait and see” approach. In this case you should have regular chest x-rays for 2 years, usually 6 months apart. It is important to be aware of the symptoms of TB disease, and to let your local TB Service or doctor know if you develop symptoms suspicious of TB.
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