Tuberculosis (TB) - Diseases and Vaccines

Immunisation
Tuberculosis (TB)

Bacteria
Tuberculosis (TB) is an infection caused by a bacterium, Mycobacterium tuberculosis (M.tuberculosis). TB most commonly affects the lungs, but it can affect other parts of the body such as the lymph nodes, bones, joints and kidneys and it can cause meningitis. With effective treatment, it is possible to make a full recovery from tuberculosis.

How is it spread
TB is most commonly spread in droplets being coughed or sneezed into the air. However, you need to have either frequent or close prolonged contact with an infected person to catch the disease. It is unlikely to be spread through spitting.

The symptoms and illness
In New Zealand, there are 300–400 cases of TB diagnosed each year. The symptoms of TB are not always specific to that disease. Also, people who are infected with TB do not always show symptoms. If they are healthy their bodies can usually stop the TB bacteria from growing. The most common symptoms are:

A cough, with or without sputum, lasting three weeks or more
Tiredness
Loss of appetite
Loss of weight
Night sweats
Coughing up blood (although this is a widely known symptom of TB, it may occur only very late and is not essential for the diagnosis).
Swollen glands (usually in the neck)

TB is treated with a combination of 3-4 antibiotics for a period of six months or more. Sometimes longer courses of treatment are needed, for example for TB meningitis, or if the bacteria are resistant to one or more antibiotics. People usually begin to feel better 2-4 weeks after starting treatment, but at least six months of drug treatment is required to make sure the disease is cured.

Neonatal immunisation in New Zealand
The current New Zealand policy is that all pregnant women should be assessed by their lead maternity carer during the antenatal period for the risk of TB for their baby. The babies identified as at risk are eligible for the Bacille Calmette-Guérin (BCG) immunisation, which should be given at birth.

Infants eligible for BCG immunisation are those who:

Will be living in a house or with family or whânau where a person has TB or a history of TB
Have one or both parents who are of Pacific ethnicity
Have parents or household members who, within the past five years, lived for a period of six months or longer in a country with a high incidence of TB
During their first five years will be living for three months or longer in a country with a high incidence of TB

It is expected that 90-95 % of people vaccinated with BCG will develop a local reaction, followed by healing and scar formation within three months.

Severe risks associated with tuberculosis
TB can be a very serious disease, sometimes resulting in:

Major haemorrhage from the lungs (now rare)
Death (this occurs in about 7% of cases, usually to elderly people)

Severe risks associated with the BCG vaccine

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

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Page last updated: 13 June 2008