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BCG complications. BCG: complications. 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.
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BCG: complications • 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 childrenJ Pediatr (Rio J) 2002; 78 (4): 289 • 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 • Will be applied to every newborn and to children up to 14 years of age • 0.1 mL IM in deltoid region • Asymptomatic newborn children with a positive HIV test must be immunized
Norma Oficial Mexicana-2000 • Contraindications • Low-weight newborns (<2 kg) • Immunosuppressed children, except asymptomatic HIV+ children • Dermatitis in the deltoid region
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 • A recent review has concluded the benefits of immunization outweigh the risk of complications. Pediatrics 1995; 95:414
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 • 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 Bull World Health Org 2003;81:61
Adverse events associated with BCG vaccination in children infected with HIV • More than 28 cases of disseminated BCG infection have been reported in HIV-infected children and adults • Progressive immune suppression can lead to the reactivation of latent BCG organisms, causing regional or disseminated disease Bull World Health Org 2003;81:61
Current Tuberculosis Vaccine Development • 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 • 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 • 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
Optimal time for giving BCG to infants • 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 • Lymphocyte response to PPD were measured at birth and at intervals • The stimulation index in infants who received vaccination at birth rose from 3.1 to 35.3 • 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
The impact of past BCG vaccination programs is difficult to assess • The introduction of BCG programs in many countries coincided with social, economic, and health changes that might themselves reduce the incidence of tuberculosis
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
We cannot expect this of BCG • 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
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 • Vaccination at birth has no effect on transmission of TB in adults, who represent the bulk of highly infectious cases
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.
The protective efficacy is uncertain and unpredictable (varied from 0 to 80%) • Protective effect against meningeal TB of 64% and against disseminated TB of 78% • Skin test reactivity resulting from vaccination does not correlate with protection against tuberculosis
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 • It may protect the immunized individuals; it will not affect the spread of the disease and thus can do little ultimately to control TB