Table 1.
Parameters used in the model, with definitions, estimated values and ranges.
| Parameter (symbol used in equations) | Estimate | Range | Country/study for estimate |
| Number of discordant couples | 1000 | Fixed | – |
| % of couples with HIV-positive woman | 93 | 85–100 | Nigeria |
| % CD4+ at ANC testing 200–350 cells/μl | 29 | 28–29 | Nigeria ANC data |
| % CD4+ at ANC testing <200 cells/μl | 13 | 13–21 | Nigeria ANC data |
| % PrEP effectiveness (efficacy × adherence θ) | 70 | 44–90 | Partners PrEP trial in Kenya and Uganda |
| % condom efficacy (e) | 80 | 58–95 | East and southern Africa; Cochrane review |
| % of sex acts in which condom used (f) | 66 | 64–80 | Rwanda; Uganda; South Africa |
| % reduction in non-condom protected acts following condom promotion | 62 | 50–62 | Rwanda; Uganda; South Africa |
| Frequency of CD4+ testing for HIV-positive people in care but not yet on ART (ρ), per year | 2 | 1–2 | Nigeria |
| % of treatment-naive accept ART (ϕ) | 68 | 65–83 | Sub-Saharan Africa; Africa, Thailand |
| Relative prob. death per month off ART, CD4+ >350 vs. 200–350 cells/μl (α1,1 : α2,1) | 0.206 | 0.206–0.258 | Cote d’Ivoire; Zimbabwe; South Africa |
| Monthly probability of death off ART, CD4+ 200–350 cells/μl (α2,1) | 0.00272 | 0.00156 – 0.00397 | Cote d’Ivoire |
| Relative prob. death per month off ART, CD4+ <200 vs. 200–350 cells/μl (α3,1 : α2,1) | 9.08 | 3.45–9.08 | Cote d’Ivoire; Zimbabwe; South Africa |
| Relative prob. death on vs. off ART for the same CD4+ cell count (αi,2 : αi,1) | 0.19 | 0.14–0.25 | South Africa |
| Off ART, monthly probability of moving from CD4+ >350 to 200–350 cells/μl (δ1,1) | 0.0257 | 0.0119–0.0289 | eART-linc cohorts in Uganda and Cote d’Ivoire; South Africa; Ethiopia |
| Off ART, monthly probability of moving from CD4+ 200–350 to <200 cells/μl (δ2,1) | 0.0188 | 0.0186–0.0274 | eART-linc cohorts in Uganda and Cote d’Ivoire; South Africa; Ethiopia |
| On ART, monthly probability of moving from CD4+ 200–350 to >350 cells/μl (δ2,2) | 0.0569 | 0.0247–0.0888 | South Africa; Europe |
| On ART, monthly probability of moving from CD4+ <200 to CD4+ 200–350 cells/μl (δ3,2) | 0.0293 | 0.0274–0.0863 | South Africa; Europe |
| Yearly % of people who dropout of ART (σ) | 10 | 5–30 | Nigeria (multiple sites); Kenya |
| Ratio of dropout from PrEP relative to ART dropout (ω : σ) | – | 1–1.5 | PrEP trials multiple sites; allowing for higher dropout expected outside trial |
| Ratio of dropout from condom promotion relative to ART dropout (κ : σ) | – | 0.3–1 | DR Congo, Uganda |
| Ratio of dropout from pre-ART care relative to ART dropout (ν : σ) | – | 1–2 | South Africa, Malawi |
| Per vaginal sex act probability of HIV transmission from man to woman (βf) | 0.0019 | 0.0010–0.0037 | Partners HIV/HSV study, multiple sites in east and southern Africa |
| % efficacy of medical male circumcision in reducing female to male HIV transmission (υ) | 0.66 | 0.4–0.77 | South Africa, Kenya and Uganda |
| % of men circumcised (τ) | 98 | Fixed | Nigeria |
| % efficacy of ART in reducing HIV transmission (χ) | 92 | 26–99 (triangular) | Meta-analysis; east/southern Africa; HPTN 052 trial (multiple countries); China |
| Relative transmission risk from HIV-positive person with CD4+ <200 vs. >200 cells/μl (ξ) | 4.18 | 2–8 | Partners in Prevention cohort, east/southern Africa |
| DALY weight HIV-positive on ART or CD4+ >350 cells/μl | 0.947 | 0.921–0.966 | Global Burden of Disease Study 2010 |
| DALY weight HIV-positive CD4+ 200–350 cells/μl | 0.779 | 0.690–0.854 | Global Burden of Disease Study 2010 |
| DALY weight HIV-positive CD4+ <200 cells/μl | 0.453 | 0.285–0.618 | Global Burden of Disease Study 2010 |
| Sex acts per month with external partners | 3.4 | 1.3–6.4 | Nigeria |
| Sex acts per month with regular partner (c) | 5.6 | 1.4–15.3 | Nigeria |
| % of sex acts condom used with external partners (men) | 49.0 | 44.9–53.1 | Nigeria |
| % of sex acts condom used with external partners (women) | 11.8 | 6.4–17.2 | Nigeria |
| ART coverage external partners (%) | 35 | Fixed | Nigeria |
| Yearly % testing for HIV, general population | 6.5 | 6.5–11.7 | Nigeria |
| Relative infectiousness of external vs. asymptomatic regular infected partner | 2 | 1–2.5 | Uganda |
| Provider unit cost PrEP initiation (2012$) | 118 | 82.6–153.4 | Nigeria, South Africa (drug costs) |
| Provider unit cost PrEP per year (2012$) | 233 | 163.1–302.9 | Nigeria, South Africa (drug costs) |
| Provider unit cost ART initiation (2012$) | 150 | 105.0–195.0 | Nigeria costing studies |
| Provider unit cost ART per year (2012$) | 365 | 255.5–474.5 | Nigeria costing studies |
| Provider costs of condom promotion per couple per year (2012$) | 19 | 13.3–24.7 | Nigeria costs for counselling, international prices for condoms |
All sources and references are given in the supplementary material. ANC, antenatal care; ART, antiretroviral therapy.