230 likes | 389 Views
Vaccination and the prospects for TB elimination Christopher Dye World Health Organization. Pulmonary tuberculosis. BCG vaccination trials 1950s. MILLENNIUM DEVELOPMENT GOALS AND BEYOND Halt and begin to reverse incidence by 2015 eliminate TB by 2050.
E N D
Vaccination and the prospects for TB elimination Christopher Dye World Health Organization
MILLENNIUM DEVELOPMENT GOALS AND BEYONDHalt and begin to reverse incidence by 2015eliminate TB by 2050 100M children get BCG annually but vaccination not mentioned
The world (of TB) is flat China S Africa India
1000-fold reduction to elimination target 10000 South Africa 10,000 fold reduction for elimination Now: 2%/yr TB cases/million/year 1000 Current tools max 10%/yr 100 New tools 20%/yr 10 Elimination <1/million 1 1990 2000 2010 2020 2030 2040 2050 Year
Efficacy of BCG vaccination in adolescents and adults: prospective studies Nurses Adolescents Mine workers Adults Adults Adults Ulleval England South Africa Madanapelle Chingleput Karonga England 0 30 50 80 90 95 Protection (%) H. Rieder 2002
Halve incidence and mortality by 2016 BCG vaccination: infants only? * Round numbers; NSP targets mix numbers and rates ** Target is to halve deaths in both HIV- and HIV+
South African population infected with M tuberculosis and protected by BCG Whole population
Characteristics of the S African TB epidemic Persistent transmission, high risk of infection 1.0 ARI 3.9%/yr up to age 5 Wood IJTLD 2010 Cape Town 0.8 Proportion TST+ 0.6 0.4 0.2 0.0 5 – 10 11 – 15 16 – 20 21 – 25 26 – 30 31 – 35 36 – 40 Age class (years)
South African population infected with M tuberculosis and protected by BCG Whole population
South African population infected with M tuberculosis and protected by BCG Uninfected 19M Infected 26M
South African population infected with M tuberculosis and protected by BCG Uninfected 19M BCG+ 3M 10M Infected 26M
BCG unprotected BCG protected Wood PLoS One 2011
Impact of BCG vaccination: infants 1400 1200 1000 TB cases/100,000/yr 800 All TB cases All cases 600 400 HIV- cases HIV+ TB cases 200 0 2000 2010 2020 2030 2040 2050 Year
BCG vaccination in combination: adults 1000 TB cases/100,000/yr 800 "BCG" E60% for 600 uninfected HIV- adults 400 Case management PT HIV+ 200 PT HIV - 0 2000 2010 2020 2030 2040 2050 Year
Proposals • M. tuberculosis induces partially protective immunity against PTB • Equalled by BCG under ideal conditions (NTM-) • Full potential of BCG under-exploited in some settings -- South Africa • Safer rBCG for HIV+ • Moving towards elimination needs a combination of interventions, including vaccination • Future, higher efficacy vaccines desirable, but more to be done with the vaccine we have today