Why the world needs vaccines for TB

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The Power of Vaccines: ‘getting to zero’ for HIV and TB was an event hosted by the TB/HIV and Prevention Working Groups of the UK Consortium on AIDS and International Development. The meeting was sponsored by Pamela Nash MP and held on Friday, 18th May 2012, in Portcullis House, Westminster. Read more at http://storify.com/PamojaUK/the-power-of-vaccines

http://www.pamoja.uk.com

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Why the world needs vaccines for TB

  1. 1. Why the world needs vaccines for TB The Power of Vaccines: ‘getting to zero’ for HIV and TB TB-HIV Working Group UK Consortium on AIDS and International Development World AIDS Vaccine Day May 18th 2012 Dr Richard White TB Centre Centre for the Mathematical Modelling of Infectious Disease Department of Infectious Disease Epidemiology London School of Hygiene and Tropical Medicine Richard.White@lshtm.ac.ukImproving health worldwidewww.lshtm.ac.uk
  2. 2. Why the world needsvaccines for TB• Global TB burden• Global TB control targets• How are we doing?• TB ‘Elimination’ - what do models have to say about how we might get there?• Summary
  3. 3. Global TB burden (2010) 10.0 8.8 Estimated number cases and 9.0 All forms TB 8.0 HIV associated TB deaths, Millions 7.0 Multidrug resistant TB 6.0 5.0 4.0 3.0 2.0 1.1 1.45 1.0 0.44 0.35 0.15 0.0 TB disease cases DeathsWHO. Global tuberculosis control 2011.Geneva.
  4. 4. Global TB disease incidence by region (2010) Americas, 5% Europe, 5% Eastern Mediterranean, • Highest burden in Asia 7% – 59% South-East Asia, • Highest rates in Africa 40% – About 80% of cases HIV infected Africa, 26% Western Pacific, 19%WHO. Global tuberculosis control 2011.Geneva.
  5. 5. Why the world needsvaccines for TB• Global TB burden• Global TB control targets• How are we doing?• TB ‘Elimination’ - what do models have to say about how we might get there?• Summary
  6. 6. Global TB controltargets• UN Millennium Development Goals – 2015: … begun to reverse [rising TB] incidence• Stop TB Partnership – 2015: 50% reduction in TB prevalence and deaths – 2050: Elimination of TB ‘as a public health problem’ (<1 case per million people)
  7. 7. Why the world needsvaccines for TB• Global TB burden• Global TB control targets• How are we doing?• TB ‘Elimination’ - what do models have to say about how we might get there?• Summary
  8. 8. How are we doing? StrategyWHO (2006). The Stop TB Strategy, WHO / StopTB. Geneva
  9. 9. How are we doing? Progress in 2011 • 46 million people successfully treated (1995-2010) • ~7 million lives saved compared to 1995 standard of care • Millenium Development Goals (declining TB disease in 2015) – Peak in ~2002 – On track • Stop TB (50% reduction in mortality between 1990 and 2015) – Reduced by 40% since 1990 in 2006 – On trackWHO. Global tuberculosis control 2011.Geneva.
  10. 10. How are we doing? Global estimated TB disease incidence, prevalence and mortality TB disease incidence TB disease prevalence TB mortality Currently ~1% annual decline Target Target 40% decline since 1990 But • TB disease incidence decline very slow • Case detection improvements slowing • MDR-TB care only now scaling upWHO. Global tuberculosis control 2011.Geneva.
  11. 11. Why the world needsvaccines for TB• Global TB burden• Global TB control targets• How are we doing?• TB ‘Elimination’ - what do models have to say about how we might get there?• Summary
  12. 12. What can we achieve with the existing strategy? Current decline (1%/yr) Predicted decline with full implementation of Global Plan to Stop TB (6%/yr) Decline required for ‘Elimination’ (16%/yr)Lonnroth et al, Social Science and Medicine, 2009
  13. 13. ‘Elimination’ by 2050 What would it take? • Impact of treating active TB disease cases OR using new pre-exposure vaccine large • But impact limited as neither directly prevents reactivation ‘Elimination’ disease among latents (1 in 3 people worldwide) • ‘Elimination’ unlikely • Elimination more likely if • Combination prevention approach used that a) Prevents reactivation disease among latents using preventative drug therapy OR a post-exposure vaccination AND b) Prevents/treats active disease using a new pre exposure vaccination OR drugDye et al, J R Soc Interface, 2008 therapy
  14. 14. Potential impact of new TB diagnostics,drugs and vaccines on TB diseaseincidence in SE Asia in 2050Diagnostics Disease incidence (/million) • Dipstick point of care test • 42% ↓ in TB incidence ) at microscopy lab level point of care testDrugs • 2 month active disease therapy Disease incidence (/million) (including M/XDR) & mass latent therapy Active disease #1: 4 month, no MDR effect Active disease #2: 2 month, 90% MDR effect Active disease #3: 10-day, 90% MDR effect • 94% ↓ in TB incidenceVaccines Disease incidence (/million) • Mass pre and post exposure vaccines + latency & case infectiousness effect • 92% ↓ in TB incidence Abu-Raddad et al, Proc Natl Acad Sci, 2009
  15. 15. Why the world needsvaccines for TB • We should meet the (rather underwhelming) target of slow annual reduction in global TB disease incidence in 2015 • Using current tools we are unlikely to get close to eliminating TB disease as a public health problem by 2050 • Can get closer to elimination using combination-prevention strategies that prevent/treat active disease AND prevent disease due to reactivation of latent infection • But, to do so we would need strategies like – mass treatment of latent MTB infection OR new post-exposure vaccine AND – high coverage of effective disease therapy OR new pre-exposure vaccine • Of these DOTS coverage increase has stalled, and mass treatment of latent MTB infection is difficult to scale up => New vaccines, drugs and diagnostics are requiredImproving health worldwidewww.lshtm.ac.uk
  16. 16. Why the world needs vaccines for TB Dr Richard White TB Centre Centre for the Mathematical Modelling of Infectious Disease Department of Infectious Disease Epidemiology London School of Hygiene and Tropical Medicine Richard.White@lshtm.ac.ukImproving health worldwidewww.lshtm.ac.uk

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