Tuberculosis is found throughout the world. Areas of particular risk include the whole of South America, Africa (sub-Saharan and North West) and the tropical Asia-Pacific regions, including the Indian subcontinent and Indonesia. Tuberculosis is a bacterial infection of the mycobacterium tuberculosis family. It is commonly spread through respiratory contact but the disease can affect any part of the body. The disease can also be spread through infected unpasteurised milk. Tuberculosis symptoms are varied and can depend upon the part of the body that has been infected. General symptoms include fever, loss of appetite, weight loss, night sweats and tiredness.
Protection for Travellers
In the United Kingdom, routine BCG vaccination for teenagers was discontinued in September 2005 and a targeted programme for higher risk groups continued. BCG vaccine is a live attenuated bacterial vaccine. BCG may be offered to un-vaccinated at risk travellers who have a negative TB skin test – the Mantoux test (see below). The decision on vaccination is dependent on individual circumstances including occupational factors. In the UK BCG vaccination is only ever given once.
Like all medicines BCG vaccine can cause side effects in some recipients. Expected reactions to the vaccination include a slight swelling, redness and tenderness at the injection site with slightly tender and swollen armpit lymph glands, this progresses over some weeks to a small ulcer with healing and then a small flat scar. Fever, headache, prominent swelling of lymph glands in the armpit, an oozing ulcer at the injection site on the upper arm are uncommon side effects. Rare effects include severe allergic reactions, inflammation of lymph glands and abscess formation and very rarely more widespread infection with the BCG bacteria.
As a live vaccine the BCG vaccination should not be given to those with impaired immunity from an underlying medical condition or treatment that affects immune response e.g. radiotherapy, corticosteroids. Acute febrile illness, active TB or known hypersensitivity to any of the vaccine constituents are other contraindications to vaccination. As with all vaccines the clinical staff will advise during the travel consultation on all aspects of the procedure including vaccine dose schedule, contraindications to vaccination, any possible interactions with other vaccines or medications, the range of possible adverse effects from the specific vaccine and any queries. Written product information to retain for reference is also provided.
Screening for latent TB
In some circumstances, you may need to be tested to check for latent TB (when you have been infected with TB bacteria, but do not have any symptoms).
For example, you may need to be screened for occupational reasons or if you have been in close contact with someone known to have an active TB infection (an infection that causes symptoms), or indeed if you have recently spent time in a country where TB levels are high.
The Mantoux test is a previously widely used test for latent TB. It involves injecting a substance called PPD tuberculin into the skin of your forearm. It's also called the tuberculin skin test (TST).
If you have a latent TB infection, your skin will be sensitive to PPD tuberculin and a hard red bump will develop at the site of the injection, usually within 48 to 72 hours of having the test. If you have a very strong skin reaction, you may need a chest X-ray to confirm whether you have an active TB infection.
If you do not have a latent infection, your skin will not react to the Mantoux test. However, as TB can take a long time to develop, you may need to be screened again at a later stage.
If you have had the BCG vaccination you may have a mild skin reaction to the Mantoux test. This does not necessarily mean you have latent TB.
Interferon gamma release assay (IGRA) - Quantiferon Gold
The TB Quantiferon Gold (IGRA) is a newer type of blood test for TB that is becoming more widely available.
The Quantiferon Gold test may be used to help diagnose latent TB:
- if you have a positive Mantoux test
- if you previously had the BCG vaccination (as the Mantoux test may not be reliable in these cases)
- as part of your TB screening if you have just moved to the UK from a country where TB is common
- as part of a health check
- if you are about to have treatment that will suppress your immune system
- if you are a healthcare worker.