IFN–γ ELISPOT in cases and household contacts in response to stimulation with ESAT–6/CFP–10 (EC) or Purified Protein Derivative (PPD), at enrolment.

<p>Peripheral blood mononuclear cells (PBMC) from TB cases and contacts were stimulated overnight (A and B) or for 6 days (C and D) with EC (A and C) or PPD (B and D) and an IFN–γ ELISPOT was performed. Horizontal lines represent the geometric mean of the spot forming units (SFU). Contacts were categorized according to TST scores at baseline and 6 months: TST⁺ = TST positive: TST≥10 mm at baseline; TSTC = TST converters: TST<10 mm at baseline and TST≥10 mm plus an increase in induration of at least 6 mm by 6 month; PTST⁻: persistently TST negative: TST<10 mm at both time^-points. P^-values represent comparisons adjusted for household, sex and gender.