Table 2

Prior biological model input parameters sampled at the fitting stage to obtain the posterior parameter sets for Mysore and Belgaum for the Avahan impact model (all durations are in months)

Types of model inputDefinition of model inputModel inputsReference for model input value
Duration of infection stagesAverage duration of Ng/Ct:Reviewed in Korenromp et al.16 Also depends on level of STI treatment.
Female sex workers (FSWs)0.5–3
Average duration of syphilis stages:Available data was reviewed by Boily et al and Garnett et al8 15
Primary (no treatment)1.51
Secondary (no treatment)3–4.5
Primary and secondary stage (with treatment)1–5
Latent phase (including treatment)2–24
Time between potential recurrences6
Immune/resistant phase12–60
Average duration of HSV-2 stages:
  • From Cheong et al, Corey et al, Diamond et al, Koelle et al, Guinan et al and Benedetti et al.17–24

  • Using Corey et al, Guinan et al and Wald et al.18 20 23 25–27

Primary stage0.36–0.66
Symptomatic recurrence0.1–0.16
Rate of HSV-2 symptomatic recurrences while:
HIV negative0.09–0.41Corey et al, Diamond et al, Benedetti et al, Lafferty et al and Kim et al18 20 21 24 28–30
HIV positive1–2×HIV negative rateUsing Schacker et al and Conant et al31 32
Average duration of HIV stages:Based on Grover and Shivraj, and Kumarasamy et al33 34
Initial HIV high viraemia phase4–6
Between initial high viraemia and pre-AIDS70–90.5
Pre-AIDS high viraemia phase6–18
Transmission probabilitiesProbability of HIV transmission per sex act:Reviewed in Holmes et al.40 67
Male to female:0.0006–0.0011
Female to male0.0001–0.0014
Sexual transmission multiplicative cofactor:
Initial high viraemia phase4.5–18.8
Pre-AIDS high viraemia phase4.5–11.9
Probability of Ng/Ct transmission per sex act0.05–0.2Reviewed by Holmes et al, Hooper et al40 67
Probability of syphilis transmission per sex act (male to female):0.1–0.3Reviewed by Garnett et al15
Ratio of transmission probabilities female to male:male to female0.33–1.0
Probability of HSV-2 transmission:
Latent/asymptomatic shedding stage (male to female)0.0005–0.002Using Wald et al and Corey et al37 38
RR male to female: female to male transmission2–5
Primary stage2–6×6.7–25 times asymptomatic/latent transmission probabilityFrom Kim et al, Wald et al and Corey et al30 37 38
Symptomatic recurrence stage1–3×6.7–25 times latent/asymptomatic transmission probabilityWald et al, Kim et al, and Mertz et al25 30 39–41
Cofactors for HIVAverage Ng/Ct cofactor per sex act for increasing susceptibility to HIV1.2–2.5Using Rottingen et al13
Average syphilis cofactor per sex act for increasing susceptibility to HIV2.1–3.3
HSV-2 cofactor per sex act for increasing HIV infectivity:
Primary and symptomatic recurrence phases1.27–2.57×1–2
Asymptomatic/latent phase0.27–1.57×0.04–0.15×2–3
HSV-2 cofactor per sex act for increasing HIV susceptibility:Using Schacker et al, Nagot et al, Zuckerman et al, Baeten et al, Celum et al, Dunne et al, Delany et al, Mbopi-Keou et al, Augenbraun et al, LeGoff et al and Serwadda et al31 42–54 and Quinn et al55 to convert from differences in HIV viral load
Asymptomatic/latent phase1–4.75
Primary phase and symptomatic recurrence phase1.5–4.0 times asymptomatic cofactor
Cofactors for HSV-2HIV cofactor per partnership for increasing HSV-2 infectivity:Using Celum et al, Corey et al, Freeman et al and Watson-Jones et al45 56–58 and converting to probability using Quinn et al55
Primary phase1–2.5
Asymptomatic/latent phase2–4
Symptomatic recurrence phaseSame as primary
Condom efficaciesCondom efficacy per sex act for HIV80% to 95%Pinkerton et al59 60
Condom efficacy per sex act for HSV-2 and syphilis40% to 70%Based on Wald et al, Oberle et al, Dobbins et al, Obasi et al and Huerta et al37 61–65
Condom efficacy per sex act for Ng/Ct60% to 90%Based on Holmes et al, Hooper et al, Austin et al, Barlow, Joesof et al, Sanchez et al, Gaydos et al, Niccolai et al and Zenilman et al 66–74
  • Ct, Chlamydia trachomatis; HSV, herpes simplex virus; Neisseria gonorrhoeae; STI, sexually transmitted infection.