Table 3

Prior behavioural model input parameters sampled at the fitting stage to obtain the posterior parameter sets for Mysore and Belgaum for the Avahan impact model

Types of model inputDefinition of model inputMysoreBelgaum
Population size and demographic inputsInitial size of sexually active population278000 (M)268000 (M)
268000 (F)257000(F)
Fraction of female general population sexually active75% to 95%77% to 95%
Fraction of male general population sexually activeDetermined by available partnershipsDetermined by available partnerships
Average time spent sexually active41.3 years (M)41.5 years (M)
42.4 years (F)42.2 years (F)
Entry rate into sexually active population per year12000 (M)12000 (M)
11000 (F)11000 (F)
Migration of female sex workers (FSWs)Proportion of FSWs migrating0.3–0.440.05–0.20
Multiplicative cofactor increasing prevalence of HIV among clients in sites to which FSWs migrate1–21–2
Sexual behaviour
Long-term partnerships of FSWs and clientsPercentage of clients currently married/cohabiting by duration:
0–1 years and 2–4 years68%43% to 59%
5–9 years and 10+ years68%83% to 93%
Percentage of FSWs currently married/cohabiting by duration:
0–1 years38.2% to 57.2%9.8% to 40.3%
2–4 years39.9% to 54.9%11.6% to 39.9%
5–9 years28.6% to 50.4%21.5% to 48.6%
10+ years23.1% to 46/7%5.3% to 20.7%
Percentage of FSWs currently married/cohabiting by typology:
Home based25.9% to 54.1%11.4% to 29.7%
Brothel based8.8% to 66.9%13.1% to 28.9%
Street based39.3% to 49.3%9.0% to 43.9%
Average frequency of sex acts with married/cohabiting partner for FSWs/clients (per month)5.9–8.2 (clients)9.5–11.7 (clients)
5.9–8.2 (FSWs)5.6–9.5 (FSWs)
Duration of long-term partnerships (cohabiting/married) if FSW, years8.6–13.016.6–21.7
Duration of long-term partnerships between clients and low-risk females, years20–3020–30
FSW sexual behaviourAverage weekly frequency of clients for:
Home-based FSWs duration 0–1 years2.5–5.15.5–26.1
Home-based FSWs duration 2–4 years3.8–7.91.8–10.3
Home-based FSWs duration 5–9 years2.8–8.25.7–10.0
Home-based FSWs duration 10+ years4.6–14.67.0–11.0
Brothel-based FSWs duration 0–1 years15–256.3–34.2
Brothel-based FSWs duration 2–4 years12–4513.5–26.2
Brothel-based FSWs duration 5–9 years4–1513.1–25.3
Brothel-based FSWs duration 10+ years5.2–16.68.9–17.9
Street-based FSWs duration 0–1 years6.5–9.24.8–13.6
Street-based FSWs duration 2–4 years7.5–9.41.1–13.0
Street-based FSWs duration 5–9 years7.2–9.82.4–10.2
Street-based FSWs duration 10+ years6.5–9.13.8–10.2
Number of sex acts with each client1–31–3
Average duration of sex work in months for:
Home-based FSWs35–69160–224
Brothel-based FSWs49–18994–127
Street-based FSWs53–66138–251
Client sexual behaviourNumber of FSWs visited/month if:
Below median activity level0.8–1.20.8–1.2
Above median activity level2.9–3.82.32–2.78
Average duration of being client in months if below/above median activity level84–240/84–24083–119/90–143
Proportions of FSWs/clients by each stratificationPercentage of female population who are FSWs0.3% to 1.4%0.2% to 1.1%
Percentage of male population who are clientsDetermined by number of FSW partnershipsDetermined by number of FSW partnerships
Proportion of FSWs that are:
Home based0.08–0.150.23–0.50
Brothel based0.00–0.010.31–0.61
Street based0.85–0.910.11–0.24
Proportion of male clients who visit FSWs:
Below median level (ie, low activity clients)0.50.58–0.69
Above median level (ie, high activity clients)0.50.31–0.42
Condom use
Condom use in main partnershipsAverage consistency of condom use between married/cohabiting partners per sex act.4.3% to 10.3%5.2% to 12.7%
Condom use between FSWs and clientsFraction of sex acts with occasional clients for which a condom is used, by FSWs who:
Report ‘always’ using0.81–0.930.81–0.93
Report often/sometimes using Report ’never’ using0.54–0.670.54–0.67
Fraction of FSWs who are consistent condom users:
At the start of the HIV epidemic in India0–0.10–0.1
Under H0 and H1:
At first time point0.111–0.2280.286–0.422
At second time point0.233–0.3950.759–0.855
Under H1, at time of IBBA R20.615–0.7290.855–0.926
Under H2:
At first time point0.1–0.2200.1–0.220
At second time point0.321–0.4160.321–0.416
At time of IBBA R20.777–0.8470.777–0.847
Fraction of FSWs who report ‘sometimes/often’ using condoms with occasional clients at IBBA R20.245–0.3670.074–0.145
DatesStart of HIV epidemic in India1976–19851976–1985
Under H0 and H1:
At first time point20022002
At second time point20042005
At time of IBBA R220072008
Under H2:
At first time point20042004
At second time point20062006
At time of IBBA R220082008
  • FSW, female sex worker; H, hypothesis; IBBA, integrated behavioural and biological assessments; R, round.