End TB strategy target setting

Philippe Glaziou

Manila, December 2014

Outline

• Rationale for global projections post-2015• TB burden assessment• Country targets

– Short-term (3-5 years)– Long-term (≥10 years)

Decline in TB burden in England and Wales

TB mortality

TB incidence

-3%/year

CFR in England and WalesGlobal CFR : 1.5 million deaths / 9 million incident

Chemotherapyintroduced

Global CFR in 2013

Slow decline in global incidence, faster decline in mortality

Incidence Mortality (including HIV)

Falling 2% per year(2007-2013)

Falling 4.7% per year(2007-2013)

Why is global TB incidence declining so slowly?

Average lifetime risk of disease 5- 15%*

World7 billion

Infected≈2.3 billion

Disease≈9 million/yr

*Am J Epidemiol Vol. 152, No. 3, 2000

Tools required for mitigating infection

• Mass Screening and Treatment may stop transmission but not TB reactivation

• Mass Prophylactic Treatment– IPT prevents 70% of reactivation in HIV-neg

Safety on a mass scale? (4-7/100,000 fatal hepatitis)Millard PS et al. West J Med. 1996 Jun;164(6):486-91.

• Mass Post-Exposure Vaccination

Business as usual

Global TB incidence rate

-2%/year

Optimize use of current tools, universal access, social protection

Business as usual

-10%/year

-5%/year

-2%/year

R&D pipelines

• No point of care test yet• 2 new drugs, little epi impact anticipated• 15 vaccines in development• New vaccine not likely until 2024

(AERAS)

Beyond 2025

Potential impact of vaccine– Introduced in 2025– 60% post-exposure efficacy– 95% coverage reached after 10 years– Assess year by which epidemic of TB could be

"ended"

~27+ billion

TB disease

Technological breakthrough by 2025 addresses the pool of infection

Business as usual

Optimize current tools

Post-exposure vaccine± safe PT

"End the global TB epidemic"

-10%/yr

-2%/yr

-5%/yr

-17%/yr

Goal: End the global TB epidemic

2025 and 2035 TB targets

TB incidence TB deaths

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10 per 100,000

-75% vs. 2015

-95% vs. 2015

Estimating TB incidence

• National incidence surveys impractical• Best documented through state-of-the

art TB surveillance. Estimates are uncertain due to– Under-reporting– Under-diagnosis

• Estimation from tuberculin surveys not satisfactory

• Prevalence surveys

Capture-recapture in Iraq

1980 detected, under-reporting = 16%473 additional cases estimated (394–565)

How else can we estimate incidence?

- From results of prevalence surveys

mortality

cure

Untreated Treated

Method 1 – deterministic model

Method 1

U T Prevalence(per 1000)

Duration(year)

Incidence(per 1000/yr)

Myanmar 2009

300 79 6.1 (5-7.5) 1.8 (1.1-1.6) 3.3 (2-4.8)

Thailand 2012

136 60 2.5 (1.9-3.5) 1.1 (0.5-1.6) 2.3 (1-3.5)

Indonesia2013

407 122 6.6 (5.2 – 8.1) 1.6 (1 – 2.2) 4.1 (2.4 – 5.8)

π ~ U (0, 0.1)

Method 2

• Reverse WHO method to estimate prevalence from incidence based on standard assumptions about disease duration (4 case categories)– Notified HIV- ~U (0.2 - 2) year– Not notified HIV- ~U (1 - 4) year– Notified HIV+ ~U (0.01 – 1) year– Not notified HIV+ ~U (0.01 – 0.2) year

Incidence in Indonesia (2013), ensemble model

Method 2(duration)

Method 1(dynamic)

Ensemble402 (276 - 552) per 100,000/year

Data on TB deaths (HIV-) from vital registration

Sources of data

• Best sources of data on TB burden are – TB notifications when data meet quality criteria

and under-reporting low and documented– TB mortality from Vital Registration with COD– Prevalence from national prevalence surveys

• Impact assessment methods tailored to the existing data

• 2015: meeting the WHO task force on TB impact measurement to review methods to evaluate the 2015 targets achievement

Short-term targetting (3-5 years)

• Monitor progress towards set target• Use a directly measured indicator

– Not incidence, not CDR, because in most cases it will not be possible to state whether the country is on track

– Mortality if Vital Registrations or sample VR– Prevalence if repeat survey within the

programme cycle– Case notifications– Treatment success

Adaptation at country level

• Short-term targets (2016-2020)– Based on a thorough epi analysis, standards

and benchmarks for surveillance– Assessment of planned actions

• Long-term targets (2025, 2035)– Project incidence and CFR over time– Target for catastrophic cost achieved if

universal access is achieved

In conclusion

• Ambitious post-2015 global targets• Country adoption of targets:

– Evaluate surveillance system– Projections

• Short-term, programme planning based on measurable indicators

• Long-term, based on indicators that will become measurable

– Acceleration of the decline in incidence– Improvements over the case fatality ratio (% of incident

cases who die from TB) faster decline of TB mortality