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.