Table 1.
Prior Parameter Values of the Transmission Model: Fixed Parameters With Identical Values in All Scenarios and Strategies
| Demographic Parameters | Value | Source |
|---|---|---|
| Birth rate, default value,a y-1 | 0.16 | [24] |
| Non-HIV related mortality: children aged <15 y, y-1 | 0.0142 | [25] |
| Non-HIV related mortality: males aged 15–<50 y, y-1 | 0.0059 | [25] |
| Non-HIV related mortality: females aged 15–<50 y, y-1 | 0.0051 | [25] |
| Non-HIV related mortality: males aged 50 y and above, y-1 | 0.0478 | [25] |
| Non-HIV related mortality: females aged 50 y and above, y-1 | 0.0422 | [25] |
| Mixing and sexual behavior | ||
| Proportion of young males engaging in high-risk behavior | 0.10 | Assumption |
| Proportion of young females engaging in high-risk behavior | 0.05 | Assumption |
| Mean duration of high-risk behavior among males, y | 25 | Assumption |
| Mean duration of high-risk behavior among females, y | 10 | [26, 27], assumption |
| Mean number of unprotected sex acts/y with regular partner | 50 | Assumption |
| Mean number of unprotected sex acts/y with casual partners: low-risk individuals | 1 | Assumption |
| Mean number of unprotected sex acts/y with casual partners: high-risk individuals | 100 | Assumption |
| Mixing (proportion of casual partners sampled exclusively from own risk group) | 0.5 | Assumption |
| Sexual transmission | ||
| Per-act transmission probability, male-to-female (chronic untreated infection), default valuea | 0.00155 | [2] |
| Per-act transmission probability, female-to-male (chronic untreated infection), default valuea | 0.00079 | [2] |
| Risk ratio for transmission probability during acute infection | 20 | [28] |
| Mother-to-child transmission | ||
| Probability of mother-to-child transmission if the mother is acutely infected | 0.313 | [29], assumption |
| Probability of mother-to-child transmission if the mother is chronically infected | 0.250 | [29, 30] |
| Probability of mother-to-child transmission if the mother is treated | 0.050 | [29], assumption |
| Natural progression of HIV | ||
| Mean duration of acute infection, y | 0.25 | [28] |
| Mean duration of asymptomatic stage, y | 4.8 | [31] |
| Mean duration of symptomatic stage before AIDS, y | 5.2 | [31] |
| HIV related mortality during symptomatic stage, y-1 | 0.1 | Assumption |
| HIV related mortality during AIDS, y-1 | 1 | |
| Treatment | ||
| Introduction of ART, y | 2003 | [23] |
| Eligibility at CD4 <350 cells/μL | 2011 | [23] |
| Universal ART eligibility | 2015 | |
| Introduction of “Option B+” | 2011 | [23] |
| Initial conditions in 1975b | ||
| Total population size | 5302000 | [32] |
| Male-to-female ratio among adults aged 15–<50 y | 1:1 | [32] |
| Male-to-female ratio among adults aged 50 y and above | 47:53 | [32] |
| Proportion of children aged <15 y | 0.469 | [32] |
| Proportion of people aged 50 y and above | 0.025 | [32] |
Abbreviation: ART, antiretroviral therapy; y, year.
aDefault value was adjusted during the calibration using a constant coefficient (Supplementary Table 5 for values).
bHIV prevalence and risk behavior in 1975 were determined in calibration (Supplementary Table 5).