why the world needs vaccines for tb
DESCRIPTION
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-vaccineshttp://www.pamoja.uk.comTRANSCRIPT
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
Improving health worldwide
www.lshtm.ac.uk
Why the world needs
vaccines 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
Global TB burden (2010)
8.8
1.451.1
0.350.440.15
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
TB disease cases Deaths
Esti
mat
ed
nu
mb
er
case
s an
d
de
ath
s, M
illi
on
s
All forms TB
HIV associated TB
Multidrug resistant TB
WHO. Global tuberculosis control 2011. Geneva.
South-East Asia, 40%
Western Pacific, 19%
Africa, 26%
Eastern Mediterranean,
7%
Europe, 5%Americas, 5%
Global TB disease
incidence by region (2010)
• Highest burden in Asia – 59%
• Highest rates in Africa – About 80% of cases HIV infected
WHO. Global tuberculosis control 2011. Geneva.
Why the world needs
vaccines 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
Global TB control
targets
• 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)
Why the world needs
vaccines 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
How are we doing?
Strategy
WHO (2006). The Stop TB Strategy, WHO / Stop TB. Geneva
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 track
WHO. Global tuberculosis control 2011. Geneva.
How are we doing?
Global estimated TB disease incidence,
prevalence and mortality
WHO. Global tuberculosis control 2011. Geneva.
Target Target
40% decline since 1990
Currently ~1% annual decline
TB disease incidence TB disease prevalence TB mortality
But • TB disease incidence decline very slow • Case detection improvements slowing • MDR-TB care only now scaling up
Why the world needs
vaccines 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
What can we achieve with the
existing strategy?
Lonnroth et al, Social Science and Medicine, 2009
Current decline (1%/yr)
Decline required for ‘Elimination’ (16%/yr)
Predicted decline with full implementation of Global Plan to Stop TB (6%/yr)
‘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 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 drug therapy
Dye et al, J R Soc Interface, 2008
‘Elimination’
Potential impact of new TB diagnostics,
drugs and vaccines on TB disease
incidence in SE Asia in 2050
Diagnostics
Drugs
Vaccines
Abu-Raddad et al, Proc Natl Acad Sci, 2009
• Dipstick point of care test
• 42% ↓ in TB incidence
• 2 month active disease therapy (including M/XDR) & mass latent therapy
• 94% ↓ in TB incidence
• Mass pre and post exposure vaccines
• 92% ↓ in TB incidence
) at microscopy lab level
point of care test
Active disease #1: 4 month, no MDR effect Active disease #2: 2 month, 90% MDR effect Active disease #3: 10-day, 90% MDR effect
+ latency & case infectiousness effect
Dis
ease
inci
den
ce (
/mill
ion
) D
isea
se in
cid
ence
(/m
illio
n)
Dis
ease
inci
den
ce (
/mill
ion
)
Why the world needs
vaccines 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 required
Improving health worldwide
www.lshtm.ac.uk
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
Improving health worldwide
www.lshtm.ac.uk