Table A Model parameters (see also table 1)
| Types of model input | Definition of model input | Model parameter | Comments of references | |
|---|---|---|---|---|
| *These variables are used to calculate the initial number of individuals in subgroup [r, j], †nrj = NrSrjΩrj. When these variables are undefined for certain r, i, and j then they take the value 1. | ||||
| Epidemiological inputs | Initial HIV prevalence among FSWs | Used to fit the model which is there after used to model the HIV epidemic with and without the intervention | ||
| Average duration of high viraemia phase (months) | 1/ν | |||
| Average duration between HIV infection and morbidity | 1/δ | Use site specific data if possible | ||
| Average duration of STI infectivity | 1/μr | |||
| Transmission probabilities | Probability of HIV transmission per sex act (male to female) | β0 | 14, 53 | |
| Ratio of probability of HIV transmission per sex act for female to male relative to male to female | Used to calculate β1 | |||
| HIV transmission cofactor during high viraemia phase | αsex | 54 | ||
| HIV transmission cofactor during STI co-infection | αs | |||
| Condom efficacy per sex act | e | 37, 55 | ||
| Size of population and general inflow/outflow | Proportion of population that have been in area for less than 1 year | Λr | Use site specific data if possible | |
| Mortality rate per 1000 person years | Ψr | |||
| Initial size of population | Nr – used to calculate nrij parameters | Nr variables are used to calculate the initial condition for nrj parameters* | ||
| Ratio of male to female population | ||||
| Sexual behaviour inputs | Definition of number of sexual partners per month for long term, casual, and commercial partnerships | Main | dr1 | |
| Casual | drj, j = 2–4 | |||
| Commercial | drj, j = 5–7 | |||
| Rate of sex acts per partnership per month | ηrj | |||
| Population distribution of males with respect to their level of sexual activity (%),γrj(r = 0) | None | S00 | Srj variables are used to calculate the initial condition for nrij† | |
| Main | S01 | |||
| Casual | S02 = S03 = S04 | |||
| Commercial | S05 = S06 = S07 | |||
| Population distribution of females with respect to their level of sexual activity (%), γŕj(ŕ = 1) | None | S10 | ||
| Main | S11 | |||
| Casual | S12 = S13 = S14 | |||
| Commercial | S15 = S16 = S17 | |||
| Mixing pattern for the distribution of long term main partnerships by category of risk of the chosen partner: degree of assortative sexual mixing between individuals of different sexual activity (0 is random mixing and 1 is full assortative mixing) | A | Little data but reviews of data from elsewhere suggest sexual mixing is usually only weakly assortative56 | ||
| Condom use inputs | Consistency of condom use among stable partnerships | f1 | Ωrj variables are used to calculate the initial condition for nrj*. “None” refers to using condoms in few sex acts (f2%), “sometimes” refers to condom being used in some (f3%) of sex acts, and “always” refers to condoms being using in nearly all of the sex acts (f4%) | |
| Population distribution of condom use among casual sexual partnerships | None | Ωr2 | ||
| Sometimes | Ωr3 | |||
| Always | Ωr4 | |||
| None | Ωr5 | “None” refers to using condoms in few sex acts (f5%), “sometimes” refers to condom being used in some (f6%) of sex acts, and “always” refers to condoms being using in nearly all of the sex acts (f7%) | ||
| Sometimes | Ωr6 | |||
| Always | Ωr7 | |||