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Research to design community based prevention

Research to design community based prevention. IAS Satellite – July 17, 2011 “Controlling the HIV epidemic – The promise of ARV-based prevention”. Planning community based interventions The trivial key q uestions. When does infection occur Where does it occur

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Research to design community based prevention

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  1. Research to design community based prevention IAS Satellite – July 17, 2011 “Controlling the HIV epidemic – The promise of ARV-based prevention”

  2. Planning community based interventionsThe trivial key questions • When does infection occur • Where does it occur • Who is most likely to transmit HIV • Who is most likely to get infected • What is the impact of behavior

  3. 30 20 % partners infected 10 0 <400 400- 3500- 10'000- >50000 3500 10'000 50'000 Blood HIV-RNA (cp/ml) Who is most likely to transmit HIVBlood and Genital Viral Load Semen HIV-RNA (cp/ml) Quinn, NEJM, 2000; 342:921-9 Beaten, Science TrslMedicine 2011

  4. PHI STDs When does HIV transmission occur?The role of PHI and STDs Infectiousness (arbritrary scale) Months / Years Weeks Vernazza et al, AIDS, 1999

  5. 0.05 0.04 0.03 0.02 0.01 0.00 0 2 4 6 8 10 12 14 16 18 20 When does HIV transmission occur?The role of Primary HIV Infection Transmission risk per sexual act Weeks after infection Pilcher et al JID 2004; 189:1785–92

  6. When does HIV transmission occur?The role of Primary HIV Infection  30% of PHI in clusters > 50% PHI clustered Brenner, JID 2007 Yerly, AIDS 2001

  7. 17 d Blood Semen 30 d PHI: Long durationofinfectivity n = 16 PHI withneg WB Malawi Pilcher et al, AIDS, 20.8.2007; 21:1723–1730

  8. Bottleneck of Transmission

  9. Not all virusesaretransmittedequally Immune system Foundervirusunchanged Redd, CROI 2011 ♯160 / Wilen, J Virol 2011 / Nawaz, PLoSPathogen 2011

  10. Who is getting infected ?HIV infections are clustered (Clade B) • 5700 Patients, >50% in 60 Clusters • Define: • Swiss clusters: Different from Intl sequ. • MSM or IDU/Het-clusters: 80% Kouyos et al, 2010 JID

  11. HIV infections in Switzerland are clusteredHIV-epidemic in HET not sustained Clustering of HIV sequences in heterosexual acquisition Kouyos et al, 2010 JID

  12. Wolf et al, AIDS 2003

  13. Conclusions • The first few months of HIV infection may be major driver of the epidemic • In Switzerland, the HIV epidemic is primarily maintained in MSM(at least clade B)

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