The impact of BCG vaccination on tuberculin skin test responses in children is age dependent: evidence to be considered when screening children for tuberculosis infection.
Thorax
; 71(10): 932-9, 2016 Oct.
Article
em En
| MEDLINE
| ID: mdl-27335104
ABSTRACT
BACKGROUND:
Following exposure to TB, contacts are screened to target preventive treatment at those at high risk of developing TB. The UK has recently revised its recommendations for screening and now advises a 5â mm tuberculin skin test (TST) cut-off irrespective of age or BCG status. We sought to evaluate the impact of BCG on TST responses in UK children exposed to TB and the performance of different TST cut-offs to predict interferon γ release assay (IGRA) positivity.METHODS:
Children <15â years old were recruited from 11 sites in the UK between January 2011 and December 2014 if exposed in their home to a source case with sputum smear or culture positive TB. Demographic details were collected and TST and IGRA undertaken. The impact of BCG vaccination on TST positivity was evaluated in IGRA-negative children, as was the performance of different TST cut-offs to predict IGRA positivity.RESULTS:
Of 422 children recruited (median age 69â months; IQR 32-113â months), 300 (71%) had been vaccinated with BCG. BCG vaccination affected the TST response in IGRA-negative children less than 5â years old but not in older children. A 5â mm TST cut-off demonstrated good sensitivity and specificity in BCG-unvaccinated children, and an excellent negative predictive value but was associated with low specificity (62.7%; 95% CI 56.1% to 69.0%) in BCG-vaccinated children. For BCG-vaccinated children, a 10â mm cut-off provided a high negative predictive value (97.7%; 95% CI 94.2% to 99.4%) with the positive predictive value increasing with increasing age of the child.DISCUSSION:
BCG vaccination had little impact on TST size in children over 5â years of age. The revised TST cut-off recommended in the recent revision to the UK TB guidelines demonstrates good sensitivity but is associated with impaired specificity in BCG-vaccinated children.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tuberculose
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Envelhecimento
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Teste Tuberculínico
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Vacina BCG
Tipo de estudo:
Clinical_trials
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Diagnostic_studies
/
Evaluation_studies
/
Guideline
/
Prognostic_studies
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Qualitative_research
/
Screening_studies
Limite:
Adolescent
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Child
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Child, preschool
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Female
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Humans
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Infant
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Male
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Newborn
Idioma:
En
Revista:
Thorax
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Reino Unido