Tuberculosis

Disease Risk Areas
Worldwide. Areas of particular risk (e.g. with more than 25 cases per 100,000 of the population) include the whole of South America, Africa (Subsaharan and North West) and the tropical Asia-Pacific regions, including the Indian subcontinent and Indonesia. (Ref.: Abstracts on Hygiene and Communicable Diseases 1995:70;177-179.)

Transmission
Most commonly spread though infected sputum, either from those with pneumonia or asymptomatic carriers. Can also be spread through infected unpasteurised milk.

Vaccination

Recommendations for Britain
In Britain most Health Authorities recommend vaccination for teenagers at around 14 years of age if they are tuberculin skin test (PPD) negative.

Recommendations for travellers
It should be ensured that travellers going to countries where tuberculosis is common have been vaccinated, especially those mixing closely with the local population such as health care workers.
It may be less important for the short-term package tourist mixing mostly with other expatriates and staying in good accommodation.
Vaccination is especially helpful in preventing meningitic and miliary forms of tuberculosis and it can be given from birth.

BCG VACCINE (Bacillus Calmette-Guerin)
Always confirm details with manufacturer's literature
Type: Live attenuated.
No of doses: 1.
Dosage: 0.1ml (0.05ml:<3m).
Route: Intradermal - traditionally given into area over left deltoid although occasionally it is given into the hip to avoid scarring in an more obvious site.
Protection: At least 10-15 years
Effective from: 6-8 weeks

A tuberculin skin test should normally be performed before vaccination except in neonates. However serious complications are unusual when vaccination is given to those who are PPD positive, although a marked PPD positive like response may develop shortly after vaccination.

Boosters
Studies in endemic areas have suggested that after a successful BCG vaccination (confirmed by a visible scar), no further protection is gained from additional doses of BCG even when PPD skin test has reverted to negative.
Whether this applies equally to travellers going from low to highly endemic areas is however not completely clear.
If booster doses are given to those going to be at high risk and who have been previously vaccinated it must be remembered that the PPD skin test may become negative due to immunocompromise (e.g. due to HIV infection or the administration of corticosteroids) when BCG can be dangerous.

Side effects
Severe injection site reactions (ulcers and abscesses) are usually caused by faulty injection technique (e.g. giving the vaccine sub-cutaneously rather than intra-dermally).
Disseminated infection can occur in those who are immunocompromised (e.g. those with HIV infection and AIDS).
Severe or persistent skin reactions can can be treated with isoniazid powder (ground up tablet) placed on the ulcer or if necessary by oral anti-tuberculous drug(s). This may prevent unnecessary scarring.
Keloid formation at the injection site is not uncommon but can usually be avoided by ensuring that the mid-upper arm or thigh is used.

Contraindications
Immunosuppression. HIV positivity. Pregnancy (delay BCG unless at high risk). Positive tuberculin skin test. Pyrexia. Generalised skin rashes.