miércoles, 2 de enero de 2019

Tuberculosis Prevention

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By Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Cantab)

Tuberculosis is a preventable and a curable disease if detected and treated early. It has a low prevalence in developed nations including the United Kingdom and the United States. This means people living in these countries and areas with low prevalence need not take precautions to prevent the infection. However, some measures of prevention are suggested for those living or travelling to areas and countries that have a high prevalence of the infection.

Tuberculosis vaccine

Bacillus Calmette-Guérin (BCG) vaccination can protect against tuberculosis. The BCG vaccine is given to all infants in countries where the disease is prevalent. In countries like the UK where it is less common it is given to those who are at risk.

Before the vaccine is given, the person is given a Mantoux skin test to check for latent tuberculosis. Vaccination is not recommended for people with latent tuberculosis.

Who is the BCG vaccine recommended for?

Currently, the BCG vaccination is recommended for three main groups of people. One of these are babies born in areas where the rates of tuberculosis is high and those babies with one or more parents or grandparents born in countries with a high rate of tuberculosis. Mantoux skin test will not be required beforehand while giving BCG vaccine to a baby.

Another group that needs BCG vaccine includes children under 16 years of age who have one or more parents or grandparents born in countries with a high rate of tuberculosis and have not been vaccinated as babies. Children under 16 who have been in close contact with someone with tuberculosis or have lived for at least three months in a country with a high rate of tuberculosis are also vaccinated with BCG after getting a Mantoux test.

The third group that requires BCG vaccination are those at high-risk occupations that includes people under 35 years of age whose occupation expose them to tuberculosis infected persons. This includes:-

health care workers (doctors, nurses and carers)
laboratory personnel who handle samples of tuberculosis
veterinary staff and other animal workers, such as abattoir workers who handle animals that may carry tuberculosis
those working in closed cramped spaces including prisoners, and hostel wardens, staff at orphanages and homes for the homeless etc.
staff at elderly care homes and refugee homes
travellers to countries with high rates of tuberculosis who plan to live there for at least 3 months

Prevention of transmission of infection

Those with pulmonary tuberculosis are contagious up to about two to three weeks once their treatment is begun. Earlier these patients were isolated. These days isolation is not practiced but some precautions are important to prevent spread. These include:-

Isolation from workplaces, schools and college and areas with crowds.
Covering one’s mouth and nose while coughing or sneezing.
Adequate and careful disposal of tissues. Usually burning or disposal in sealed plastic bags is recommended.
Sharing beds and rooms with un-infected persons while sleeping should be avoided.

Getting treatment for latent infections

Contacts of tuberculosis patients are evaluated for latent tuberculosis. Latent tuberculosis is suspected if they are:-

Interferon-gamma positive OR
Mantoux positive (either 6 mm or greater without prior BCG vaccination or strongly positive (≥15 mm) with prior BCG vaccination), OR
Presence of tuberculosis nodules on chest X ray without history of adequate treatment

These latent tuberculosis patients need to be treated with anti-tubercular drugs to prevent spread and flaring up of the infection. Treatment is either six months of isoniazid or three months of rifampicin and isoniazid combination.

If the person exposed to tuberculosis is HIV positive 6 months of isoniazid is preferred. Those who have been exposed to people with isoniazid-resistant tuberculosis get 6 months of rifampicin.