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Southern Africa out of control

1200. Swaziland. Southern Africa out of control. South Africa. 800. Zimbabwe. Namibia. Botswana. Lesotho. Zambia. 400. 1990. 2007. Southern Africa. Zambia. Western Cape. 0. 15. 30 Km. Western Cape. Zambia. 0. 200. 400 Km.

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Southern Africa out of control

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  1. 1200 Swaziland Southern Africa out of control South Africa 800 Zimbabwe Namibia Botswana Lesotho Zambia 400 1990 2007
  2. Southern Africa Zambia Western Cape 0 15 30 Km Western Cape Zambia 0 200 400 Km A community randomized trial of two interventions delivered to ~1,000,000 people while strengthening the existing health systems P. Godfrey-Faussett, H. Ayles, N. Beyers Map Source: Google Earth October 2007
  3. Enhanced Case finding (ECF) Community Mobilization and sputum collection School intervention Open Access at the clinic Guiding Principles Every person able to give sputum within 30 min walk Sputum smear results within 48 hours
  4. Household Intervention (HH) Using a TB patient as the Gateway to a household at risk of TB and HIV 3 visits (0,2, completion TB treatment) Group education TB/HIV TB screening HIV testing (group, couple, individual) Counselling and referral for care
  5. Actual Trial Total Population 962,655 6 communities per arm Primary endpoint: Prevalence of TB Enhanced case finding (ECF) Vs no ECF Household Intervention (HH) Vs no HH Secondary Endpoint: Community level: TB transmission
  6. Prevalence surveys Random sample of adults living in each of 24 communities Geographically based clustered sample used Every adult equal chance of being picked Respiratory sample collected from every consenting adult and cultured on MGIT
  7. Field work Flow Household visited 55,450 No consent from household 7,055 Household enumerated 48,395 Eligible Individuals 123,790 Individuals not found or no consent 33,189 Individual Consent 90,601 Questionnaire Respiratory sample HIV test, blood sugar
  8. Laboratory methods Sample receipt Samples transported to 5 laboratories (furthest site 800 km) Each sample inoculated on two manual MGIT tubes Reduce proportion of contaminated samples Increase yield QA: Each batch of samples processed with one positive and negative control Each laboratory working at maximum capacity (100 per day in each mini-lab, 200 per day in centralised lab) Isolate identification ZN stain MPB 64 Ag test 16s rRNA gene sequencing done on samples that were either ZN stain positive or MPB64 positive
  9. Laboratory Flow Consented 90,601 Batch rejected due to QA failure 16,710 Both cultures Contaminated 9,461 Evaluable Culture 64,430 M.tb (16S) 884 No TB 63,546
  10. Prevalence of TB Zambian sites Prevalence 542/100,000 adults (SD 263) Community range 221-1,096/100,000 South African sites Prevalence 2,319/100,000 adults (SD 487) Community range 1489-3054/100,000
  11. Prevalence 880/100,00 (Ref) Prevalence 780/100,000 Adj RR 0.82 (0.64-1.05) P=0.07
  12. Prevalence 940/100,000 Adj RR 1.09 (0.85-1.40) P=0.48 Prevalence 730/100,00 (Ref)
  13. Transmission endpoint Longitudinal design Direct measure of incidence of tuberculous infection Follow children TST negative at baseline and measure rate of TST conversion Advantage over repeated cross sectional design in that cumulative incidence would be acquired throughout child’s life and not just for the duration of the interventions Trial outcome, so favour specificity over sensitivity
  14. 2nd TST Survey results 12,075 children seen, assented, injected and read at 2nd survey. 8809 negative at baseline. Median follow-up period was 4 years (IQR: 3.5-4.7) .
  15. TST conversion rate (per 100 person-years) against baseline prevalence of TB infection in 6-11 year olds
  16. Summary Community randomized trial conducted in 24 communities in Zambia and Western Cape SA Great need for interventions to reduce TB and HIV HH intervention reduced the prevalence of culture positive TB by 18% HH intervention also associated with an important reduction in incidence of tuberculous infection in children No effect seen from ECF intervention
  17. Future Directions ZAMSTAR has built a huge team involving researchers, communities and health systems Platform for the PopART (HPTN 071) study Builds on ZAMSTAR household counselling intervention to deliver universal coverage of combination prevention and test and treat
  18. Lessons for impact evaluations Heterogeneity of communities Opportunity for interventions Challenge for trial design TB>HIV Herd effects TB and HIV intervention trials need to be huge Need to understand transmission networks HIV incidence similar to TB incidence rates TB and HIV intervention trials need to be huge
  19. ZAMSTAR Team; Communities; Participants; Zambian Ministry of Health; Western Cape Provincial and South African National Department of Heath; CREATE; Bill and Melinda Gates Foundation (Grant No. 19790.01)
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