1 / 19

Modeling vaccination strategies for developing countries

Modeling vaccination strategies for developing countries. DIMACS meeting May 17-20, 2004 Annelies Van Rie. Childhood mortality. More than 10 million deaths that occur globally in children age < 5 2002: millenium goals: reduce childhood mortality by two thirds by 2015.

bjoseph
Download Presentation

Modeling vaccination strategies for developing countries

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Modeling vaccination strategies for developing countries DIMACS meeting May 17-20, 2004 Annelies Van Rie

  2. Childhood mortality • More than 10 million deaths that occur globally in children age < 5 • 2002: millenium goals: reduce childhood mortality by two thirds by 2015. • 1990: 180/1000 in sub-Saharan Africa • 1990: 9/1000 in industrialized countries • 2000: 175/1000 in sub-Saharan Africa • 2000: 6/1000 in industrialized countries • Neonatal disorders and infectious diseases are the important causes

  3. Black et al(Lancet, 2003) prediction for 42 countries contributing 90% of CH deaths Neonatal disorders: 33% (29-36) Diarrhea: 22% (14-30) Pneumonia: 21% (14-24) Malaria: 9% (6-13) AIDS: 3% Measles: 1% (1-9%) 2000 WHO estimates prediction for all WHO member states Neonatal disorders: 42% Diarrhea: 13% Pneumonia: 19% Malaria: 9% AIDS: 3% Measles: 5% Global causes of child deaths • a substantial proportion (24%) are caused by vaccine preventable infections (Lara Wolfson)

  4. Vaccines for children • Vaccines are one of the grand successes of the 21st century. • The impact has been substantially larger in the developed word • Vaccines have been developed to preferentially address the epidemiology of infectious diseases in high income countries • Malaria (9%) • Meningococcal (type C scale 2 logs less compared to type A)

  5. Childhood vaccination: 2 worlds or many more? • Double standard or 1 standard • Rotavirus • Thiomersal • polio • Disease burden in developing countries vs disease burden in developed countries • How do can we help countries in determining priorities? • Capacity building (human, laboratory) • Country typology

  6. Black et al. Lancet 2003;361:2226

  7. Barriers to use of existing childhood vaccines • Lack of disease burden data • Need of cold chain • Poor transportation and storage systems • Inadequate and poorly motivated HCW • Budget constraints • Lack of political will Obaro et al. Vaccine 2003

  8. Barriers to use of “new” vaccines • Lack of disease burden data • Budget constraints • Lack of political will

  9. Improving vaccine use in developing countries (1) • Advocate its use • Generation of local burden of disease data (disease surveillance systems, regional sentinel sites) • Demonstration of immunogenicity, efficacy and safety in the local population • Cost effectiveness data (1 vaccine or comparisons?) • Inform policy makers, opinion leaders and HCW • Inform the community through mass media

  10. Improving vaccine use in developing countries (2) • Pay for its use (GAVI) • Immunization Systems Strengthening (ISS) support –performance/reward based system • New Vaccine Support (NVS) – vaccine provided for 1st five years

  11. Improving vaccine use in developing countries (3) • Decrease costs of vaccines (local production) • Develop easy to use vaccines (no cold chain) • Decrease the number of dosages • Pertussis: elimination of 1 childhood dose • Hib : 3 dose instead of 4 in UK • Pneumococcal vaccine: 1 dose instead of 4? • Italy: 26% coverage 1-year olds plus 31-53% catch up gives 91% reduction in invasive Hib disease (Gallo et al. Vaccine 2002) • US: largest decrease in invasive disease in 65+ (Whitney at el. NEJM 2003) • Fractional dose • Hepatitis B: 10-fold dilution with equivalent Ab avidity in South African study (Lagos et al, Lancet 1998) Obaro et al. Vaccine 2003

  12. Improving vaccine use in developing countries (4) • Targeted vaccination • Who to vaccinate? • Importance of unvaccinated pockets? • Importance of differences between rural and urban? • WAIFW differences? • Acquaintance immunization (Cohen et al. Physical Review letters 2003) • Vaccination of randomly selected acquintances of randomly selected persons • Large Household vaccination (Ball et al. Ann Appl Prob. 1997) • Vaccinees chosen sequentially from those households with the largest number of susceptibles

  13. Improving vaccine use in developing countries (5) • Targeted vaccination • PLACE based vaccination: not WHO but WHERE • Limitation of contact tracing in infectious disease control • Identification of geographic clustering and high transmission areas (HTA) for HIV • Role of locations in transmission of infectious disease: TB transmission in bar, restaurant, dancing hall, church, crack house, rock concert, prison, shelters in developing countries, piqueras in Mexico and shebeens in SA

  14. PLACE • Priorities for Local AIDS Control Efforts • AIDS prevention programs should focus on places where people with high rates of new sexual partnership formation meet new sexual partners • Available demographic and epidemiologic contextual data help to identify places where individuals with highest rates of new partnership formation meet new partners; • To minimize bias, the method does not primarily rely on self-reported behavior, contact tracing, naming of sexual partners, or require information about self-reported behavior except to validate information obtained in other ways; • The method is feasibly implemented in a short period of time without outside technical experts • The method provides program indicators useful for intervention monitoring. Weir et al. Sex Transm Inf 2002

  15. PLACE for HIV and TB (method) • Township in Cape Town, South Africa and in Kinshasa, Democratic Republic of Congo. • Selection of PLACE venues likely to have a high HIV incidence of infection based on epidemiological, socio-demographic and behavioral information via key informants • site visits, site interviews • Information was on TB symptoms (Cape Town) and presence of active TB (Kinshasa).

  16. PLACE for HIV and TB (results) • 3482 persons interviewed for risk behavior and TB symptoms. • Chronic cough was present in • Cape Town (221 PLACE venues) : • 15% of 621 men • 12% of 356 women • Kinshasa (63 PLACE venues) • 15% of 948 men • 11% of 245 women • Kinshasa ( 7 STI clinics) • 11.5% of 69 male and 8% of 234 female clients • Kinshasa (2 ANC clinics) • 2.4 % of 1035 pregnant women. • 15 (9%) of 163 Kinshasa participants reporting chronic cough, had active TB confirmed by bacteriological methods • HIV infection: STI > PLACE venues >> ANC

  17. PLACE for HIV and TB (use) • Prevention efforts • Education • Condom distribution • Diagnosis • VCT • TB • Intervention ? • STI syndromatic treatment • TB treatment DOT • HIV treatment DOT

  18. PLACE for VACCINATION • Focus on places where forces of infection are highest • Use available demographic and epidemiologic contextual data to identify areas most likely to have high forces of infection

  19. Conclusion • To reduce childhood mortality we need action now • Traditional advocacy methods have been slow and small in effect • GAVI has sustainability issues • Value of innovative ideas: can modeling help?

More Related