Serial monogamy and the spread of HIV

1. Serialmonogamy and the spread of HIV How explosive can it get? Wim Delva MD, PhD Carel Pretorius MSc, PhD Stijn Vansteelandt MSc, PhD Marleen Temmerman MD, PhD Brian Williams MSc, PhD

2. 3. Serial monogamy and the spread of HIV Department of Health, South Africa, 2009 26

3. The compartmental model R10C Sero-discordantcasualrelationship R10L Sero-discordantlong-termrelationship 27

4. The compartmental model R10C R11C ν(τ) Sero-concordantcasualrelationship ν(τ) R10L R11L Sero-concordantlong-termrelationship ν= HIV transmissionrate τ = timessinceinfection 27

5. The compartmental model f CσC R10C R11C ν(τ) ν(τ) R10L R11L f LσL σ = partner turnoverrate f = assortativeness parameter 27

6. The compartmental model f CσC R10C R11C ν(τ) (1-f C)σC (1-f L)σL ν(τ) R10L R11L f LσL σ = partner turnoverrate f = assortativeness parameter 27

7. The compartmental model f CσC R10C R11C ν(τ) (1-f C)σC (1-f C)σC (1-f L)σL (1-f L)σL ν(τ) R10L R11L f LσL σ = partner turnoverrate f = assortativeness parameter 27

8. The compartmental model μ(τ) μ(τ) f CσC R10C R11C ν(τ) (1-f C)σC (1-f C)σC (1-f L)σL (1-f L)σL ν(τ) R10L R11L f LσL μ(τ) μ(τ) μ = HIV-relatedmortalityrate 27

9. Uncertaintyanalysis 28

10. Results Fraction of simulations Doubling time (years) 29

11. Results Base case Fraction of R0 in 1styear R0 Doubling time (years) 30

12. Sensitivityanalysis 31

13. How to geta DT of 1.2 years? 31

14. Conclusions • Serial monogamyunlikely to result in doubling time of 1.2 years or less • The South African HIV epidemicisunlikely to have emergedfrom a seriallymonogamoussexual network • Serial monogamyreduceseffect of high acute infectiousness • New modelsneeded to capture the effect of concurrencyrealistically • Otherpotential (partial) explanations: • Anal sex, MSMW, unsafemedical injections 32

15. Thanks • IWT(FlemishInstitute for Innovation through Science and Technology) • FWO(FlemishResearchFund) 50