Evaluation of the Ethiopian Millennium Rural Initiative: impact on mortality and cost-effectiveness.

MAIN OBJECTIVE: Few studies have examined the long-term, impact of large-scale interventions to strengthen primary care services for women and children in rural, low-income settings. We evaluated the impact of the Ethiopian Millennium Rural Initiative (EMRI), an 18-month systems-based intervention to improve the performance of 30 primary health care units in rural areas of Ethiopia. METHODS: We assessed the impact of EMRI on maternal and child survival using The Lives Saved Tool (LiST), Demography (DemProj) and AIDS Impact Model (AIM) tools in Spectrum software, inputting monthly data on 6 indicators 1) antenatal coverage (ANC), 2) skilled birth attendance coverage (SBA), 3) post-natal coverage (PNC), 4) HIV testing during ANC, 5) measles vaccination coverage, and 6) pentavalent 3 vaccination coverages. We calculated a cost-benefit ratio of the EMRI program including lives saved during implementation and lives saved during implementation and 5 year follow-up. RESULTS: A total of 134 lives (all children) were estimated to have been saved due to the EMRI interventions during the 18-month intervention in 30 health centers and their catchment areas, with an estimated additional 852 lives (820 children and 2 adults) saved during the 5-year post-EMRI period. For the 18-month intervention period, EMRI cost $37,313 per life saved ($42,366 per life if evaluation costs are included). Calculated over the 18-month intervention plus 5 years post-intervention, EMRI cost $5,875 per life saved ($6,671 per life if evaluation costs are included). The cost effectiveness of EMRI improves substantially if the performance achieved during the 18 months of the EMRI intervention is sustained for 5 years. Scaling up EMRI to operate for 5 years across the 4 major regions of Ethiopia could save as many as 34,908 lives. SIGNIFICANCE: A systems-based approach to improving primary care in low-income settings can have transformational impact on lives saved and be cost-effective.

The potential impact of an HIV vaccine with rapidly waning protection on the epidemic in Southern Africa: examining the RV144 trial results.

BACKGROUND: The prime-boost HIV vaccine regimen used in the recent RV144 trial resulted in modest efficacy of 31% over 3.5 years, but was substantially higher in the first year post-vaccination. We sought to explore the potential impact of a vaccine with rapidly waning efficacy in a South African population. METHODS: We explored two strategies using a dynamic compartmental epidemic model for heterosexual transmission of HIV: [1] vaccination of a single cohort (30%, 60% or 90% of the initial population), with exponentially waning efficacy, but booster vaccinations at 5- or 2-year intervals, and [2] continuous vaccination of the unvaccinated population at the same coverage levels (30%, 60% or 90%) but with a constant efficacy vaccine of short duration. We also examined potential changes in post-vaccination condom use. RESULTS: The single cohort vaccination strategies did not have a substantial impact on HIV prevalence, although without boosters they still prevented 2-6% of the expected infections at 20 years, depending on the population coverage. The 5-year and 2-year booster strategies prevented 8-24% and 17-45% of the expected infections, respectively. Continuous vaccination to maintain population coverage levels resulted in more substantial reductions in population HIV prevalence and greater numbers of infections prevented: HIV prevalence at 20 years was reduced from 23% to 8-14% and the number of expected infections was decreased by 34-59%, depending on the population coverage level. Moderate changes in post-vaccination condom use did not substantially affect these outcomes. CONCLUSIONS: An HIV vaccine with partial efficacy and declining protection similar to the RV144 vaccine could prevent a substantial proportion of HIV infections if booster vaccinations were effective and available. Our estimates of the population impact of vaccination would be improved by further understanding of the duration of protection, the effectiveness of booster vaccination, and whether the vaccine efficacy varies between subpopulations at higher and lower risk of exposure.

The potential impact of a moderately effective HIV vaccine with rapidly waning protection in South Africa and Thailand.

BACKGROUND: Although published data from the recent ALVAC/AIDSVAX trial in Thailand (RV144) indicated the HIV vaccine provided very modest protection overall (31.2%), new analysis of trial data has suggested higher efficacy levels earlier in the follow-up period. CDC and UNAIDS organized several modeling research teams to explore the implications of the trial results and potential utility of this vaccine. METHODS: We explored the impact of a vaccine with moderate but rapidly waning protection (78%, 1.43 years) using an exponential decay function fit to trial data. We varied program coverage levels (20-80%), vaccine efficacy (30-90%), timing (single or multi-year programs), targeting (general or populations at higher risk), and background levels of all other prevention programs (constant or scaled-up). We simulated these various vaccination scenarios in two representative countries using demographic projections generated with Spectrum modeling software. We assumed the vaccine becomes available in 2020 and target coverage is achieved by 2025. RESULTS: A general vaccination strategy in South Africa covering 60% of the population, for example, would prevent 3.0 million infections between 2020 and 2030-36% of expected infections-and would be very effective, requiring only 39 vaccinations/infection averted. The same strategy in Thailand would prevent 81,000 infections-35% of expected infections-but would require 1725 vaccinations/infection averted. Targeting only populations at higher risk of exposure in Thailand would reduce total vaccinations given by more than ten-fold and would still prevent 52,000 infections-23% of expected infections-while requiring only 220 vaccinations/infection averted. Outcomes were sensitive to program coverage, vaccine efficacy and background levels of all other prevention programs. CONCLUSIONS: A vaccine with rapidly waning protection could have a substantial impact on the epidemic in South Africa and Thailand. Due to the short duration of effect, large numbers of vaccinations would be needed to maintain high population coverage levels. Further research into the immunological effects of booster vaccinations is warranted.

Scaling up circumcision programs in Southern Africa: the potential impact of gender disparities and changes in condom use behaviors on heterosexual HIV transmission.

Circumcision significantly reduces female-to-male transmission of HIV infection, but changes in behavior may influence the overall impact on transmission. We sought to explore these effects, particularly for societies where women have less power to negotiate safe sex. We developed a compartmental epidemic model to simulate the population-level impact of various circumcision programs on heterosexual HIV transmission in Soweto. We incorporated gender-specific negotiation of condom use in sexual partnerships and explored post-circumcision changes in condom use. A 5-year prevention program in which only an additional 10% of uncircumcised males undergo circumcision each year, for example, would prevent 13% of the expected new HIV infections over 20 years. Outcomes were sensitive to potential changes in behavior and differed by gender. For Southern Africa, even modest programs offering circumcision would result in significant benefits. Because decreases in male condom use could diminish these benefits, particularly for women, circumcision programs should emphasize risk-reduction counseling.

Predicting the impact of a partially effective HIV vaccine and subsequent risk behavior change on the heterosexual HIV epidemic in low- and middle-income countries: A South African example.

We developed a mathematical model to simulate the impact of various partially effective preventive HIV vaccination scenarios in a population at high risk for heterosexually transmitted HIV. We considered an adult population defined by gender (male/female), disease stage (HIV-negative, HIV-positive, AIDS, and death), and vaccination status (unvaccinated/vaccinated) in Soweto, South Africa. Input data included initial HIV prevalence of 20% (women) and 12% (men), vaccination coverage of 75%, and exclusive male negotiation of condom use. We explored how changes in vaccine efficacy and postvaccination condom use would affect HIV prevalence and total HIV infections prevented over a 10-year period. In the base-case scenario, a 40% effective HIV vaccine would avert 61,000 infections and reduce future HIV prevalence from 20% to 13%. A 25% increase (or decrease) in condom use among vaccinated individuals would instead avert 75,000 (or only 46,000) infections and reduce the HIV prevalence to 12% (or only 15%). Furthermore, certain combinations of increased risk behavior and vaccines with <43% efficacy could worsen the epidemic. Even modestly effective HIV vaccines can confer enormous benefits in terms of HIV infections averted and decreased HIV prevalence. However, programs to reduce risk behavior may be important components of successful vaccination campaigns.