Low uptake of isoniazid window prophylaxis in patients exposed to a health‐care worker with pulmonary tuberculosis in a paediatric ward

AIM: A nurse on a paediatric multidisciplinary ward was diagnosed with smear-positive pulmonary tuberculosis. Children <2 years old, immunocompromised, or >40 h of contact (n = 173) were contact-traced. METHODS: Children received clinical review, chest X-ray, tuberculin skin test (TST; <5 years old) and/or an interferon-gamma release assay (Quantiferon TB-Gold, ≥5 years old). Infants <6 months old or children <5 years old screened <2 months from exposure were recommended isoniazid window prophylaxis (WP) until a repeat TST at 6 months old or 8-10 weeks after the last exposure to the index case, respectively. Empiric treatment for latent tuberculosis infection (LTBI) was individually considered for immunocompromised patients. RESULTS: Of 173 children (135 immunocompetent, 38 immunocompromised), two were uncontactable, seven refused screening and two immunocompromised children excluded. Eight of 126 immunocompetent children were diagnosed with LTBI (initial TST positive n = 7, TST conversion n = 1); seven started isoniazid. Thirty-two of 36 immunocompetent children were recommended WP; 15 accepted (one non-compliant after 1 month). Six of seven immunocompromised children accepted empiric LTBI treatment due to severe immunosuppression/initial indeterminate Quantiferon TB-Gold result. Of 15 immunocompromised children offered WP, only five accepted. CONCLUSIONS: There was high acceptance of screening but low uptake of isoniazid WP in high-risk children exposed to pulmonary tuberculosis. Perception of exposure risk and chemoprophylaxis should be explored further.