Asymptomatic Tuberculosis in Children with Household Exposure to Mycobacterium tuberculosis

Abstract

Background: Asymptomatic tuberculosis (TB) is common in adult community prevalence surveys. Evidence to inform our understanding of asymptomatic TB in children is lacking, since diagnostic algorithms typically include only symptomatic children.

Methods: Children aged 2-60 months, without HIV, with household exposure to an adult TB patient in the last year, were enrolled in South Africa. Symptom screening, chest radiography (CXR) and induced sputum were performed. Confirmed TB (requiring positive Xpert Ultra and/or MGIT culture) and Unconfirmed TB (requiring two of TB exposure, compatible symptoms, or compatible CXR) were defined by application of a consensus case definition for classification of childhood TB. Asymptomatic TB was defined as Confirmed or Unconfirmed TB without reported symptoms.

Results: 430 TB-exposed children, median age 25.9 (IQR 13.5-40.0) months, were enrolled. 154 (35.8%) children met TB diagnostic criteria, including 21 (4.9%) Confirmed and 133 (30.9%) Unconfirmed cases. 55 (35.7%) of all TB cases were asymptomatic, including 17/21 (81.0%) Confirmed and 38/133 (28.6%) Unconfirmed cases. CXR was compatible with TB in 30/41 (73.2%) asymptomatic versus 15/47 (31.9%) symptomatic cases who underwent CXR (p<0.001). TB treatment was started in 44/55 (80%) asymptomatic versus 34/99 (34.3%) symptomatic cases (p<0.001). Factors associated with asymptomatic compared to symptomatic TB included microbiological confirmation (aOR=3.73; 95%CI 1.08-12.88).

Conclusion: Asymptomatic TB that meets the consensus case definitions for both Confirmed and Unconfirmed disease is common in TB-exposed children. All child household contacts should be actively investigated for TB, regardless of symptoms, before a decision is made on curative or preventive therapy.

Keywords: Tuberculosis; asymptomatic; children; contact; household.