Ikushi Onozaki WHO/STB/TBS Global Task Force on TB Impact Measurement

The role of prevalence surveys in measuring the burden of TB,

progress in TB control and improving early case detection

Ikushi Onozaki

WHO/STB/TBS

Global Task Force on TB Impact Measurement

DEWG meeting, Oct 13-14 2009, Geneva

Background

Task Force recommendations

What is needed to implement a survey and what can surveys tell us?

Current status of survey implementation

Next steps

Content

TB prevalence is an MDG indicator that can be directly measured in HBCs

Estimation of TB burden using tuberculin surveys no longer applicable in most settings

Funding is available for surveys, and governments and international agencies recognize importance of measuring impact

Background

Task Force recommendations

Countries where surveys are recommended

21 global focus countries36 additional countries that met basic criteria

How should surveys be implemented?

Follow the guidelines!

Recommended screening strategy

Do smear and culture at least for with TB symptoms and/or abnormal chest X-ray

What is needed to implement a survey?

( WHO headquarters, March 2008)

Sample size : 30,000- 60,000

Cluster size: 500-1,000

12-15 staff per field team for 6–10 months, 3-4 team operation

Costs ~ US$1 million in Asia, US$2 million in Africa Capital investment (CXR, Lab, Cars), Human Resource (Salaries), Survey Operation (Field and Central), Pre & Post survey events, technical assistance

What is required for a survey?

Go to the community

Survey day

Transport people to X-ray site

Individual interview by trained health professional from central unit

• TB related symptoms

• TB history– Possible treatment– Consultation Places

• Risk factors

Develop and read images on the SpotQuality Direct X-ray is Available in Villages

that contributed to high participation rates and 100% sputum collection from suspects

Prevalence Survey in Viet NamDigital technology was introduced for the first time to National Scale TB survey

Smear Microscopy

Direct Smear, ZN

LED-FL

Collect, Store, Transport and Put in Culture within 5 days

Lab work

What can be learned from a survey?

A carefully designed survey can tell you lots more than TB prevalence

• Changes in TB burden and re-estimation of burden

• Performance of strategies for screening of TB suspects

• Health-seeking behaviour of TB patients and individuals reporting chest symptoms

• Where and why are cases missed by the NTP e.g. access to care, role of private sector

• Risk factors

•Prevalence of Sm+ TB in Cambodia, 2002, was half of previous estimate and previous study results

•Prevalence of S+ in Yangon, Myanmar, nearly 3 times previous national estimate -> National Survey

•Prevalence of S+ in Viet Nam, 2007, was 60% more than previous estimate

Prevalence Surveys can help to revise and improve estimates of disease burden and CDR

Re-estimation of TB Burden

Strategies for screening TB suspects

No Chronic Cough No symptomS+ Bac + Bac +

Cambodia 38% 61% 15%

Zambia 57% 10%

Viet Nam 40% 45% 25%

NTP Cambodia. National TB Prevalence Survey Report, 2002. 2005, ** H Ayles et al. Plos one May 2009. e 5602, *** NTP Viet Nam. Presented in UNION APR Conference, Beijing, Sept 2009

40-60% of confirmed cases in surveys do not have chronic cough

Smear microscopy alone misses >50% of bacteriologically-confirmed TB

*Africa 5 sub-national surveys average

S+/ Bac+Cambodia 2002 30%

Philippines 2007 43%

Korea 1995 41%

Africa* 01- 05 34%

Where are cases being missed?

64 participants were on TB treatment

52%

34%

9%5%

NTP 33

GP 22

Other 6

Unknown 3

33 in NTP: around 130/100,000 = 260/100,000/year

Yangon survey, 2006: 1/3 of TB patients being treated by GPs

Current status of survey implementation

Good progress in Asia

Completed Next Protocol Budget

Cambodia 2002 2010 Finalizing Almost secured

China 2000 2010 Finalizing ditto

Philippines 2007 2017? (disseminating)

Viet Nam 2007 2012 (disseminating)

Completed Next Protocol Budget

Bangladesh 2009 ? Analyzing

Indonesia 2004 2012? To be proposed

Myanmar (1994) 2009 (Ongoing) Secured

Thailand (1991) 2011 Drafting Secured

Pakistan (1987) 2010 Final draft Secured

No survey in Africa started yet – urgent action required!!

Completed Next Protocol Budget Ethiopia - 2010 Final draft Almost secured Kenya - 2010 Final draft Applied Mozambique - Feasibility assessment Nigeria - 2010 Final draft Partially secured South Africa - 2010 Revising National budget Tanzania - 2010 Finalized Partially Uganda - 2010 Reviewed Partially

HBC

Other countries preparing: Ghana, Malawi, Mali, Rwanda, Togo, Zambia,

Next steps

Workshop on prevalence surveys in 12 African countries, 15-16 October 2009

• Identification of bottlenecks holding up survey implementation

• Lessons from Asia

• How to solve the bottlenecks

• Role of Task Force partners in providing technical assistance to countries