Table 1– Tuberculosis (TB) cases among contacts by risk factor status and period of follow-up
CharacteristicPopulation at risk at start of contact nvestigation nTotal TB cases n (%)Prevalence of TB at time of initial contact screening#Risk for incidence of TB 3 months to 2 years after initial screeningIncidence of TB 3 months to 2 years after initial screeningRisk for incidence of TB ≥2 years after initial screening+Incidence of TB ≥2 years after initial screening+
n% (95% CI)Person-years at risk nPersons at risk nnper 100 000 (95% CI)Person-years at risk nPersons at risk nnper 100 000 (95% CI)
All contacts14 371273 (1.9)2121.48 (1.26–3.12)21 51814 15950232 (174–309)40 31814 1091127 (14–50)
Age years§
 0–1423696 (1.9)381.60 (1.15–2.22)362923316165 (67–379)62322325232 (6–129)
 15–345335128 (2.4)981.84 (1.50–2.24)7698523726338 (225–502)15 0085211427 (9–73)
 ≥35574099 (1.7)761.32 (1.05–1.66)8830566418204 (125–329)17 3625646529 (11–71)
Sexƒ,##
 Male6125123 (2.0)1021.67 (1.37–2.03)9131602319208 (129–331)17 2606004212 (2–47)
 Female7475149 (2.0)1091.46 (1.20–1.76)11 205736631277 (191–398)21 6777335942 (20–82)
TB incidence (per 100 000) in country of birth¶¶
 Australian-born <10 per 100 000535746 (0.9)390.73 (0.53–1.00)80335318675 (30–171)16 287531216 (0.3–40)
 Overseas-born <10 per 100 00064115 (2.3)111.72 (0.90–3.15)9696303310 (80–982)1979627151 (3–327)
 Overseas-born 10–99 per 100 000280074 (2.6)592.11 (1.62–2.73)4240274114330 (188–568)80052727112 (1–81)
 Overseas-born >100 per 100 0003245138 (4.3)1033.17 (2.61–3.85)4763314227567 (381–836)84883115894 (44–194)
TST size++,§§
 TST ≥10 mm (including results prior to contact investigation)4307N/AN/A6635430732482 (336–689)12 6794275971 (35–140)
 TST <10 mm8073N/AN/A12 2478073433 (10–90)23 26980690
 TST result unknown or not done1779N/AN/A2636177914531 (302–913 )37571765253 (9–214)
Preventive treatment§§,ƒƒ
 All preventive treatment received548N/AN/A8585482233 (40–936)1653546160 (3–392)
 TST ≥10 mm, preventive treatment received409N/AN/A6334092316 (55–1266)1313407176 (4–493)
 TST ≥10 mm, no preventive treatment received3942N/AN/A6002394230500 (343–722)11 3653912870 (33–145)
  • TST: tuberculin skin test; N/A: not available. #: Includes all TB cases among contacts diagnosed within 90 days of the first healthcare contact for screening; : the denominator is person-years at risk, the 212 contacts who were diagnosed with TB at the time of the initial screening are excluded; +: the denominator is person-years at risk, the 262 contacts who were diagnosed with TB at the initial screening or within the first 2 years of follow-up are excluded; §: data available for n=13 444; ƒ: one contact with TB was classified as “transgender”, thus female and male cases total 272 instead of 273 cases; ##: data available for 13 600; ¶¶: data available for 12 043; ++: data available for 12 417; §§: only includes contacts during follow-up period (without the 212 contacts who were diagnosed with TB at the time of the initial screening); ƒƒ: data available for 14 159.