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What I wish modelling could do for global health. Peter Piot Institute for Global Health 4 th December 2009. Tropical medicine. Geographic medicine. International Health. Global Health. Colonial. Post-colonial. End of cold war. Globalisation.
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What I wish modelling could do for global health Peter Piot Institute for Global Health 4th December 2009
Tropical medicine Geographic medicine International Health Global Health Colonial Post-colonial End of cold war Globalisation
Funding Total annual resources available for AIDS, 1986 ‒2007 US$ million 10 billion 10 000 8.9 billion 9000 Signing of Declaration of Commitment on HIV/AIDS,UNGASS 8000 8.3 billion 7000 6000 World Bank MAP launch 5000 4000 Gates Foundation PEPFAR 3000 UNAIDS Less than US$ 1 million 2000 1623 1000 Global Fund 292 257 212 59 0 ‘06 2007 1986 ‘87 ‘88 ‘89 ‘90 ‘91 ‘92 ‘93 ‘94 ‘95 ‘96 ‘97 ‘98 ‘99 ‘00 ‘01 ‘02 ‘03 ‘04 ‘05 Notes: [1] 1986-2000 figures are for international funds only [2] Domestic funds are included from 2001 onwards [i] 1996-2005 data: Extracted from 2006 Report on the Global AIDS Epidemic (UNAIDS, 2006) [ii] 1986-1993 data: AIDS in the World II. Edited by Jonathan Mann and Daniel J. M. Tarantola (1996)
Modelling for Global Health • Interpretation • Prediction and anticipation • Creation of hypothesis • Implications of policy options • Evaluation • Identification of data needs • Advocacy
Behavioural change, impact in urban and semi-urban Zimbabwe M1: assuming behavioural change, better fit to surveillance data Natural decline in incidence ~1990 Accelerated decline in incidence, due to behaviour change ~2000 M0: without behavioural change Source: Hallett TB, et al. Epidemics 2009;1(2):108-117
Cambodia, 1988-2004 45000 40000 35000 30000 25000 20000 15000 10000 5000 0 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Male clients Sex workers Wife from husband Husband from wife Mother to child Number of new HIV infections by route of transmission Source: Peerapatanapokin and Brown, using Asia Epidemic Model
Real-time modelling • FMD, SARS showed the potential of real-time modelling (statistical and dynamical). • Initial goal – ‘now-casting’ – correcting for censorship/delays in case/mortality reporting • Aims – estimate R, mortality, generation time distribution, predict future trends, evaluate sufficiency of control measures. • Important new approach – inferring infection trees – developed in 2001 then further in 2003 for SARS. • Require data though – need to set realistic expectations. 7 2 5 8 1 3 6 9 10 4
World population by age groups, 1950-2050 Source: United Nations Population Division 2006. “World Population Prospects: The 2006 Revision”
Predicted expansion of dengue in Africa 1990 2085 This projection uses an scenario that delivers a three fold increase in CO2 by 2100 Source: Hales S et al. Lancet. 2002;360(9336),830-834.
Geographic origins of emerging infectious diseases events from 1940 to 2004 Source: Jones KE et al. Nature 2008:451;990-993.
AIDS spending (share of gross domestic product) and adult HIV prevalence in 2030 Source: Hecht R et al. Health Affairs 2009;28(6):1591-1605
Population impact of treatment as prevention Time trends resulting from application of universal voluntary HIV testing and immediate ART strategy for people who test HIV positive, in combination with other adult prevention interventions that reduce incidence by 40% Source: Granich RM, et al. Lancet 2009; 373: 48–57.
Policy impact of treatment as prevention Source: Bulletin des médecinssuisses | SchweizerischeÅrztezeitung | Bolletinodeimedicisvizzeri | 2008;89:5 and www.hivandhepatitis.com
Hep B vaccination strategies in the Netherlands Targeting vaccination to high-risk groups can be cost effective, despite being demanding in effort and logistics. Universal vaccination of all neonates or all adolescents has the greatest potential at the cost of having to vaccinate large numbers of individuals Will it be possible to increase coverage of risk groups to acceptable levels or is universal vaccination the way to ensure satisfactory vaccination coverage of high-risk groups? Source: Kretzschmar M et al. Lancet Infectious Diseases 2008;8(2):85-87 .
HPV vaccination - need for continued screening and appropriate health-care messages Source: Garnett GP et al. Vaccine 2006;24(3):S178-S186.
Long term view: Effects of Prevention on Future Costs of ART
Interaction of circumcision interventions with existing behaviour change programmes Projected effect of different prevention interventions on HIV incidence Source: Hallett TB, et al. PLoS ONE 2008;3(5): e2212
Measles outbreaks in a population with declining vaccine uptake Source: Jansen VAA, et al. Science 2003;301:904.
Synergy needed • Science • Politics • Money • Programme delivery Source: Koplan JP et al. Lancet 2009;373:1993.
Recorded female deaths in South Africa and Brazil for ages 15-64 years Brazil, 2004. South Africa, 1997. South Africa, 2004 Source: Nathan Geffen. Statistics South Africa and InstitutoBrasileiro de Geografia e Estatistica.
Need for real-life effectiveness evaluations • Seguro Popular is a new set of health reforms aiming to provide health coverage to 50 million uninsured Mexicans. 23% reduction from baseline in catastrophic expenditures • 30% reduction in poor households and 59% in experimental compliers Source: King G et al. The Lancet 2009: 373(9673):1447-1454
Data Needs: Concurrency and HIV Concurrent partnerships have been hypothesised as one of the main factors behind the HIV epidemics in sub-Saharan Africa for the past 15 years, with empirical evidence providing different conclusions. It was only a few days ago that the Working Group on Measuring Concurrent Sexual Partnerships (UNAIDS Reference Group on Estimates, Modelling, and Projections) published a consensus paper on indicators for concurrency . The Lancet, article in press: doi:10.1016/S0140-6736(09)62040-7 Source: Morris M et al. AIDS 1997;11(5):641-648.
Advocacy : cost and impact of male circumcision Total net cost of male circumcision programme (US dollars) New adult HIV infections by scenario Source: Bollinger et al. Journal of the International AIDS Society 2009 12:7.
A new agenda for global healthNew challenges for modellers • Finalize the unfinished agenda! • Chronic diseases and mental health • Population growth, climate change, urbanization, water • Deliver new prevention& treatment technologies • More effective health systems
Projected deaths by cause for high-, middle-, and low-income countries Source: WHO World Health Statistics 2008 http://www.who.int/whosis/whostat/EN_WHS08_Full.pdf
Network analysis of obesity in the Framingham cohort Largest connected subcomponent of the social network in the Framingham Heart Study in 2000. Probability that an ego will become obese according to the type of relationship Source: Christakis NA et al. NEJM 2007:357(4);370-379.
What do we need more from modellers? • Explore connections between disease dynamics and structural determinants • Use more than one modelling approach per issue • Regularly validate past and present modelling • Engage with evaluation of complex health interventions to generate counterfactuals against which to compare observed trends.