Transcript TB and the Mexican Border: BCG, Practices & Complications

BCG complications
BCG: complications
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Local ulcers and
regional lymphadenitis
in normal hosts: 4 to 30
per 1000 vaccinated
infants
Osteomyelitis (0.1 to 30
per 100,000 doses)
Disseminated BCG
infection (0.1 per
100,000 doses
Death: 0.02 per million
BCG revaccination in school children
J Pediatr (Rio J) 2002; 78 (4): 289
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Induration was present in 99.1% and
erythema in 91.6% of 438 children
evaluated within 48h
Pustules were observed in the first week
in 26.1% of 479 children. The first ulcers
were seen during the second week
By the tenth week, 69.8% of 463 children
showed crusts but only 29.2% completed
the healing process
Norma Oficial Mexicana-2000
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Will be applied to every newborn and to
children up to 14 years of age
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0.1 mL IM in deltoid region
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Asymptomatic newborn children with a
positive HIV test must be immunized
Norma Oficial Mexicana-2000
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Contraindications
o Low-weight newborns (<2 kg)
o Immunosuppressed children, except
asymptomatic HIV+ children
o Dermatitis in the deltoid region
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It is recommended that where the risk of
childhood TB is high, BCG should be
given to infants as early as possible,
even if mothers are known to have HIV
infection
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A recent review has concluded the
benefits of immunization outweigh the
risk of complications.
Pediatrics 1995; 95:414
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A consensus view currently exists,
however, that BCG should not be given to
infants with active HIV disease and that
the vaccine is contraindicated in older
asymptomatic children who are found to
be HIV positive.
Immunization of children at risk of
infection with HIV
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The available data is not adequate to
permit definitive conclusions about the
effectiveness of BCG vaccine to protect
HIV-infected children or adults against
tuberculosis.
Bull World Health Org 2003;81:61
Adverse events associated with BCG
vaccination in children infected with HIV
Dissemination
0-31%
Lymphadenitis
0-24%
Bull World Health Org 2003;81:61
Adverse events associated with BCG
vaccination in children infected with HIV
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More than 28 cases of disseminated BCG
infection have been reported in HIV-infected
children and adults
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Progressive immune suppression can lead
to the reactivation of latent BCG organisms,
causing regional or disseminated disease
Bull World Health Org 2003;81:61
TB vaccines: the future
Current Tuberculosis Vaccine
Development
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Advances in mycobacterial molecular
genetics and the establishment of the
genome sequence of Mycobacterium
tuberculosis, make it possible to generate
a vast new repertoire of potential TB
vaccine candidates
Current Tuberculosis Vaccine
Development
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An improved vaccine that would provide
greater protection against M.
tuberculosis, although technically
feasible, is still far from being an
achievable goal.
First US TB vaccine trial in 60
years begins
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A new vaccine, made with several
proteins from MTB will enter the first
phase of human safety testing
This is the first recombinant TB vaccine to
reach human trials in the US
It combines two TB proteins known to
stimulate strong immune responses in
humans
NIH News Jan 2004
Timing for BCG immunization
Optimal time for giving BCG to infants
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There is some evidence to suggest that
later immunization during infancy may
confer a higher degree of immunity.
BCG immunization at 3 months of age
was found in one study to provide a
higher rate of tuberculin protein skin
responses with fewer complications than
when given during the first three days of
life.
Arch Dis Child 1999; 80:80
Timing of BCG vaccination in Canadian
Cree infants
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Lymphocyte response to PPD were
measured at birth and at intervals
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The stimulation index in infants who
received vaccination at birth rose from 3.1 to
35.3
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The SI in infants who were immunized
between 9 months and 2 years rose from 2.2
to 52.9 (p<0.05)
Am Rev Respir Dis 1989; 140:1007
Impact of BCG vaccination
on the TB epidemic
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The impact of past BCG vaccination
programs is difficult to assess
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The introduction of BCG programs in
many countries coincided with social,
economic, and health changes that might
themselves reduce the incidence of
tuberculosis
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Many of the vaccines we use routinely in
children induce herd immunity—breaking
the transmission of infection from one
individual to the next, protecting thereby
the unimmunized as well as the immunized
and resulting in dramatic reductions in
incidence
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We cannot expect this of BCG
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The vaccine, given to infants and children,
may protect the immunized individuals
(somewhat unreliably) but will do little
else to check the spread of the disease
and thus can do little ultimately to control
TB
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Children with TB pose a negligible
infectious risk to others. They acquire TB
not from each other but, for the most part,
from adults with TB not preventable by
BCG
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Vaccination at birth has no effect on
transmission of TB in adults, who
represent the bulk of highly infectious
cases
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Vaccination at school-leaving age,
practiced in Britain and in Norway, was
developed to address this deficiency, but
so far there has been no unequivocal
demonstration of the effectiveness of this
strategy in reducing transmission of M.
tuberculosis.
Conclusions
1. The protective efficacy is uncertain and
unpredictable (varied from 0 to 80%)
2. Protective effect against meningeal TB of
64% and against disseminated TB of 78%
3. Skin test reactivity resulting from
vaccination does not correlate with
protection against tuberculosis
4. BCG should not be given to infants with
active HIV disease; it is contraindicated
in older asymptomatic children who are
found to be HIV positive
5. It may protect the immunized
individuals; it will not affect the spread
of the disease and thus can do little
ultimately to control TB