FIRS The Global Impact of Respiratory Disease – Second Edition | Page 22
Prevention
In no disease is the phrase “treatment is
prevention” truer than with TB. The factors
promoting the spread of infection relate to
the chance that an uninfected individual is
exposed to a person with infectious TB: the
more cases in the community, the more likely
it is that an individual will become infected.
Factors promoting the development of
disease in infected individuals generally relate
to the function of the immune system. The
most potent factor causing an exposed person
to develop active tuberculosis is infection with
HIV, but other conditions that affect immunity,
such as certain medications and the presence
of poorly controlled diabetes, also increase
the risk of developing active disease.
Inhaling only a few tuberculous bacteria can
result in infection. However, only about one
in 10 people infected with Mycobacterium
tuberculosis will develop active disease,
although the rate is much higher in young
children and people with immunodefi ciency
conditions. TB lies dormant because the
infection is contained by the body’s immune
system, but it can become active at any point
in a person’s lifetime. This two-phase sequence
by which the disease develops provides an
opportunity for prevention. By identifying
persons who are proven or are highly likely
to have latent infection and treating those
who have conditions or circumstances that
increase the risk of disease, the likelihood
of developing active TB can be substantially
reduced. Several drug regimens have been
documented to be effective for treating latent
tuberculosis [35].
Treatment in all healthcare sectors and countries. The
long duration of therapy (usually 6 months
with four drugs in uncomplicated cases)
makes adherence to treatment challenging,
especially in individuals who are taking other
medications for chronic diseases, such as
HIV infection. Failure to take the full course
of prescribed drugs appropriately may
result in relapse with drug-resistant disease,
which is more diffi cult to treat and poses a
risk to others. For this reason, supervised or
directly observed therapy is recommended
as the standard of care to ensure adherence
throughout the course of treatment.
Most cases of TB can be cured if diagnosed
early and treated appropriately using
standardised approaches that are based on
evidence derived from clinical trials. The
International Standards for Tuberculosis
Care [36] should be followed by providers Treatment of patients with multidrug-resistant
TB is a more complicated issue. Although
the standard has been to treat with fi ve or
six drugs for 14–18 months, a recent trial has
shown a shorter course of therapy is better
[37] and now recommended by WHO.
The current vaccine, Bacille–Calmette–Guérin
(BCG), offers only partial protection against
TB but does reduce the risk of disseminated
TB and tuberculous meningitis in children.
Research centres around the world are working
on developing a better vaccine for TB.
Forum of International Respiratory Societies
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