Hygeia and Panacea: is prevention better than cure? - PowerPoint PPT Presentation

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Hygeia and Panacea: is prevention better than cure?

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  1. Hygeia and Panacea: is prevention better than cure? CHRISTOPHER DYE What's the single best method of prevention or cure ever devised to improve public or personal health?

  2. Prevention is better than cureDangerous myth… “Dad always thought laughter was the best medicine, which I guess is why several of us died of tuberculosis.”

  3. Prevention is better than cure …or universal truth? Scurvy, "limeys" and vitamin C James Lind 1716-94 A Treatise of the Scurvy

  4. Treatise on Preparation for Death On Civility in Children Adagia "Prevention is better than cure" Desiderius Erasmus 1466-1536

  5. 1. When prevention is better than cure

  6. Where 60 million people die double burden of disease in low-income countries 8 Low-middle income High income 6 Deaths per million population 4 2 0 Communicable, Non- Injuries pregnancy, communicable nutrition

  7. Currency of illness and death WHAT'S THE HUMAN COST OF RABIES… …AS COMPARED WITH HEART DISEASE?

  8. Currency of illness and death HOW TO COMPARE RABIES WITH HEART DISEASE? DISABILITY-ADJUSTED LIFE YEAR (DALY) DALY = YEARS LOST TO ILLNESS × DISABILITY WEIGHT + YEARS LOST BY DEATH

  9. An ounce of prevention or a pound of cure?

  10. Tobacco tax works! Cigarette sales New Zealand 8 14 7 12 $ price 20 cigarettes Millions sold 6 10 5 8 4 6 1980 1985 1990 1995 2000 2005

  11. DALYs: all we need to know? Prevention or treatment of terminal cancer? Choose: • Palliative treatment to extend days of healthy life in people with cancer Or: (b) Preventive measures (advertising, taxation etc) to reduce cancer incidence Assume cost per DALY is the same

  12. Climate & health: An inconvenient truth? "The benefits of strong, early action on climate change outweigh the costs" STERN REVIEW November 2006: The Economics of Climate Change

  13. Michael Mann's "hockey stick"

  14. Global warming: damage to health

  15. Easier and harder ways to keep CO 2 at or below 550 parts per million 70 Delayed action 60 Prompt action 50 Stabilization beyond reach? 40 Global emissions (GtCO2) Stabilization feasible 30 20 10 0 2000 2020 2040 2060 2080 2100

  16. "The cost of investment would be trivial by comparison with the possible damage" Investment 1% per year of global GDP over next 50 years Damage 2-3 ºC : 0-3% GDP in late 21st century 5-6 ºC : 5-20% GDP ($4 trillion per year)

  17. Market Bond Bond… Financing sanitation and vaccines Human Development Report 2006 “the rates of return from upfront investment in water and sanitation would significantly outweigh the costs of borrowing from bond markets…”

  18. Smallpox: what value eradication? Day 3 Synchronous eruption of lesions Day 5 Rash turns to vesicles and pustules Day 7 Large lesions with central well Case fatality 30%

  19. From inoculation to vaccination to eradication DA Henderson WHO Eradication campaign (1966-1977) Lady Mary Wortley Montague (1689-1762) Edward Jenner (1749-1823)

  20. Smallpox inoculation: tools of the trade

  21. "Just eradicate the disease, and let the skeptics talk to each other" UNICEF Cost of eradication in external funding $125 million

  22. 1967 About 10,000 cases per month 1977 Last case 26 October 1977

  23. Poliomyelitis: prevention far better than cure

  24. Polio vaccines Sabin & Salk

  25. Polio eradication?>1600 cases in 2006 Total external spending ~ $4 bn Initial estimate $300 million India Pakistan Afghanistan Nigeria

  26. 2. When cure is the only option

  27. Leprosy: curable but not preventable

  28. 3. When cure is also prevention

  29. TUBERCULOSIS: 1.7 MILLION DEATHS ANNUALLY 100000 Cure Prevention 10000 1000 Cost/yr healthy life gained ($/DALY) 100 10 1 Treat latent Treat BCG Treat active infection resistant TB vaccination TB

  30. 4. When cure is the sister of prevention

  31. Hygeia and Panacea cleanliness (and healing) are next to godliness Asklepios - medicine and healing Hygeia - cleanliness Panacea - healing

  32. DIARRHEA: 1.8 MILLION DEATHS/YEAR methods for prevention and cure 5000 Cure 4000 Prevention 3000 Cost/year healthy life ($/DALY) 2000 1000 0 Latrines Water pump Oral rehydration Water & sanitation Cholera or rota vacc Breastfeeding promo

  33. The 60 countries with the highest numbers or rates worldwide of child mortality

  34. Child deaths: task is not to choose prevention or cure, but to implement all feasible solutions target -4.3% Sub-Saharan Africa South Asia Middle East Latin America Europe & Central Asia East Asia Faster economic -5 -4 -3 -2 -1 0 growth Fall 1990-2000 Annual fall in child mortality (U5M %)

  35. Effective prevention and cure

  36. 5. How individuals approach prevention and cure

  37. Why take the risk? Are you "risk averse" or "risk prone"? • Plain ignorance (AIDS is not curable) • It'll never happen to me (delusional) • The future may never come (discounting) • Peer pressure (Kool and the Gang) • For kicks (excitement, bore/freedom) • Refusal to pay for insurance

  38. Risk, roulette and health insurance

  39. see www.gresham.ac.uk

  40. 6. Magic bullets & Nobel Prizes

  41. Cure is cleverer than prevention?186 Nobel Prizes for Medicine, 1901-2006 Basic science 172 Cure/therapy 12 Prevention 2 Theiler 1905 Ehrlich 1908 + Mechnikov 1908

  42. Paul Ehrlich's (1854-1915)"magic bullets" Prevention: "side-chain" theory of immunity based on antibody Cure: drugs selectively targeting pathogens -- arsenic-based Salvarsan to treat syphilis Smoking one of his "25 strong cigars a day" Died of stroke

  43. Magic bullets, besides penicillin… Fleming Chain Florey 1928/41

  44. Aspirin (acetylsalicylic acid, 1899) • Analgesic against minor pains and aches • Antipyretic against fever • Anti-inflammatory against arthritis • Anti-platelet blood-thinner • Anti-stick stops bacteria growing on contact lenses • Side effects gastrointestinal distress (ulcers, stomach bleeding), tinnitus, bleeding in menstruation

  45. Sir John Vane, Nobel Prize 1982 Aspirin reduces strokes in women (17%) and heart attacks in men (32%) women have slightly more strokes than heart attacks, men tend to have more heart attacks than strokes (JAMA vol 295, p 306, 2005)

  46. Praziquantel vs schistosome flukes

  47. 250 million people infected with schistosomes Adult flukes killed with a single dose of PZQ

  48. Is prevention better than cure? In formal analysis, not necessarily… • Aetiology of some diseases unknown some conditions unpreventable • Prevention vs cure is not always the right question both are needed and feasible e.g. child mortality in LDCs • We value more than is captured in formal analysis which gives guidance, not rules