Tuberculosis disease

Tuberculosis (TB) is an infectious disease caused by infection with the bacterium Mycobacterium tuberculoisis. TB most commonly affects the lungs, but can also affect the lymph nodes, bones, joints and kidneys. It can also cause meningitis.

Summary

In New Zealand, there are approximately 300 cases of tuberculosis (TB) diagnosed each year. New Zealand meets the World Health Organization definition of a low TB incidence country. Almost 4 out of every 5 TB cases in New Zealand (2011-2015) were born outside New Zealand (particularly South and Central Asia). Approximately half of all New Zealand born cases of TB (from 2011-2015) were of Māori ethnicity.

While life-threatening complications such as haemorrhage from the lungs are now rare, TB can still be a very serious disease, particularly for older people.

TB is spread through coughing, sneezing or spitting. The bacteria are carried into the air and people nearby can breathe them in through their mouths and noses.

You need to live or work closely with an infected person to catch the disease.

TB can stay inactive in someone’s body for many years before it develops. This is called latent tuberculosis infection. Even though you feel well and healthy, the doctor may still advise treatment to make sure you do not develop TB disease. Go to Latent tuberculosis to find out more.

TB can be treated with antibiotics. It’s very important to finish the treatment or the disease will get worse again.

TB vaccinations are normally only given to:

  • babies at risk of catching TB from someone living in their house
  • babies who are going to live in a country with a high rate of TB
  • babies whose parents, household member or carer have in the last 6 months lived in a country with a high rate of TB.

Symptoms

People with tuberculosis (TB) don’t always show symptoms. If you’re healthy, your body can usually stop the TB bacteria from growing.

Symptoms of TB can be similar to other illnesses. The most common symptoms are:

  • a cough lasting 3 weeks or more, often with thick phlegm
  • tiredness
  • night sweats
  • weight loss
  • swollen glands (usually in your neck).

Coughing up blood is a widely known symptom of TB, but if this occurs, it will happen a long time after someone is infected.

If you think you may have TB, it’s important to see your doctor. They can arrange tests to see if you’re infected.

Treatment

With treatment, tuberculosis (TB) can almost always be cured. It’s very important to finish the course of antibiotics, or the disease may come back again and the bacteria may become resistant to the antibiotics.

TB is treated with a combination of antibiotics, which need to be taken for at least 6 months. Sometimes longer courses are needed, such as for TB meningitis.

People usually begin to feel better 2–4 weeks after starting treatment.

You can’t catch TB from a person who has been taking the antibiotics for 2 weeks or more.

Prevention

BCG vaccine

The BCG vaccine helps protect against severe forms of tuberculosis (TB) by helping the immune system fight against it. In New Zealand, the BCG vaccine is not recommended for the general population because the rates of TB are quite low in many parts of the country.

Most people who are vaccinated against TB develop a small blister around the injection site. Within 3 months this should heal and form a scar.

Vaccination for babies

Babies at risk of catching TB can be given the BCG (Bacille Calmette-Guérin) vaccination when they’re born.

If you’re pregnant, your lead maternity carer will assess the risk of TB for your baby. They’ll ask questions like:

  • Will your baby be living in a house with a person who has TB or has a history of TB?
  • During their first 5 years, will your baby be living for 3 months or longer in a country with a high TB rate?
  • Within the last 5 years, has a parent or carer or the baby, or household member, lived for 6 months or longer in a country with a high TB rate?

If the answer to any of these questions is yes, your baby is eligible for the BCG vaccination.

Vaccination for other people

  • Children under 5 years of age who are at risk of TB exposure are also eligible for BCG vaccine.
  • In some circumstances the local medical officer of health may also recommend BCG vaccination for specific populations.

Which countries have a high TB rate?

In general, the following places are considered to have a high TB rate (≥ 40 per 100,000):

  • most of Africa
  • much of South America
  • Russia and the former Soviet states
  • Indian subcontinent
  • China, including Hong Kong
  • South East Asia (except Singapore)
  • some Pacific nations (except Cook Islands, Niue, Samoa, Tokelau and Tonga).

Making a decision about vaccination

Most people who are vaccinated against TB develop a small blister around the injection site. Within 3 months this should heal and form a scar.

Risks associated with tuberculosis

TB can be a very serious disease, sometimes resulting in:

  • major haemorrhage from the lungs (now rare)
  • death (now rare, more likely in elderly people).

Risks associated with the BCG vaccine

Are very rare – 387 out of 1 million infants may develop enlarged lymph nodes and a local abscess.

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