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TB-infected mothers:
Babies born to mothers who develop tuberculosis
disease shortly before or shortly after
delivery are not protected sufficiently
quickly by BCG given at birth to avoid the
possibility of becoming infected. Neonates
should be given daily isoniazid (5 mg/kg)
for six months as prophylactic chemotherapy.
BCG, which is inactivated by chemotherapy,
can be given after it ends.
Repeat
(booster) vaccination: Booster
doses should not be given. Many countries
still recommend repeat vaccination but there
is no evidence that it is effective.
Duration
of effect: Too little is known
of the duration of protection given by BCG.
Information on this matter is essential
for estimating the impact of BCG vaccination
programmes.
High-risk
subgroups: Many countries have
a low prevalence of tuberculosis in the
majority of their populations but still
have small numbers of high-risk individuals,
such as immigrants who have just arrived
from places where the prevalence of the
disease remains high. In such situations,
BCG is offered only to infants at high risk.
HIV
infection: BCG should not be
given to children with symptomatic HIV infection
(i.e. AIDS). In asymptomatic children, the
decision to give BCG should be based on
the local risk of tuberculosis:
- Where the risk of tuberculosis is
high, BCG is recommended at birth or
as soon as possible thereafter, in accordance
with standard policies for immunization
of non HIV-infected children;
- In areas where the risk of tuberculosis
is low but BCG is recommended as a routine
immunization, BCG should be withheld
from individuals known or suspected
to be infected with HIV.
In practice, few if any
neonates are likely to have symptoms of
HIV infection and should therefore receive
BCG vaccine. Cases of BCG-itis in adult
AIDS patients have suggested that viable
BCG can remain for a long period in vaccinated
individuals. The extreme rarity of these
cases, however, after almost two decades
of the HIV pandemic, favours the continuation
of the present policy.
Criteria
for discontinuation: Increasing
numbers of developed countries are likely
to shift from routine to selective BCG vaccination
during the next decade. WHO supports the
International Union Against Lung Disease
(IUATLD)'s criteria that provide a rough
guide for this decision. An efficient notification
system must be in place, and one of the
following:
- an average annual notification rate
of smear-positive pulmonary tuberculosis
below 5 per 100 000;
or
- an average annual notification rate
of tuberculous meningitis in children
under five years of age below 1 per
10 million population over the previous
five years;
or
- an average annual risk of tuberculous
infection below 0.1%.
Further work is needed
on the cost-benefit ratio of BCG as opposed
to that of other approaches to control.
One argument favoring the discontinuation
of BCG is based on the advantages inherent
in the absence of non-specific BCG-induced
tuberculin sensitivity. This would facilitate
the use of tuberculin testing for contact
tracing, source identification and the selection
of individuals for preventive therapy. This
is a valid argument but many years would
have to elapse after the discontinuation
of routine BCG vaccination before a vaccinated
population could be completely replaced
with unvaccinated individuals.
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The
best way to prevent the spread of TB is
to diagnose the infection as quickly as
possible and treat the infection appropriately.
One should complete the prescribed treatment
to get successfully treated. One should
not discontinue the tablets without consulting
the doctor, as it would result in drug
resistance and make matter worse.