title: Cost-effectiveness of tenofovir gel in urban South Africa: model projections of HIV impact and threshold product prices.
abstract: BACKGROUND
  There is urgent need for effective HIV prevention methods that women can initiate. The CAPRISA 004 trial showed that a tenofovir-based vaginal microbicide had significant impact on HIV incidence among women. This study uses the trial findings to estimate the population-level impact of the gel on HIV and HSV-2 transmission, and price thresholds at which widespread product introduction would be as cost-effective as male circumcision in urban South Africa.
  
  
  METHODS
  The estimated 'per sex-act' HIV and HSV-2 efficacies were imputed from CAPRISA 004. A dynamic HIV/STI transmission model, parameterised and fitted to Gauteng (HIV prevalence of 16.9% in 2008), South Africa, was used to estimate the impact of gel use over 15 years. Uptake was assumed to increase linearly to 30% over 10 years, with gel use in 72% of sex-acts. Full economic programme and averted HIV treatment costs were modelled. Cost per DALY averted is estimated and a microbicide price that equalises its cost-effectiveness to that of male circumcision is estimated.
  
  
  RESULTS
  Using plausible assumptions about product introduction, we predict that tenofovir gel use could lead to a 12.5% and 4.9% reduction in HIV and HSV-2 incidence respectively, by year 15. Microbicide introduction is predicted to be highly cost-effective (under $300 per DALY averted), though the dose price would need to be just $0.12 to be equally cost-effective as male circumcision. A single dose or highly effective (83% HIV efficacy per sex-act) regimen would allow for more realistic threshold prices ($0.25 and $0.33 per dose, respectively).
  
  
  CONCLUSIONS
  These findings show that an effective coitally-dependent microbicide could reduce HIV incidence by 12.5% in this setting, if current condom use is maintained. For microbicides to be in the range of the most cost-effective HIV prevention interventions, product costs will need to decrease substantially.
authors.affiliation: London School of Hygiene & Tropical Medicine, London, UK. Fern.Terris-Prestholt@lshtm.ac.uk.
authors.forename: Fern
authors.initials: F
authors.lastname: Terris-Prestholt
authors.forename: Anna M
authors.initials: AM
authors.lastname: Foss
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Cox
authors.forename: Lori
authors.initials: L
authors.lastname: Heise
authors.forename: Gesine
authors.initials: G
authors.lastname: Meyer-Rath
authors.forename: Sinead
authors.initials: S
authors.lastname: Delany-Moretlwe
authors.forename: Thomas
authors.initials: T
authors.lastname: Mertenskoetter
authors.forename: Helen
authors.initials: H
authors.lastname: Rees
authors.forename: Peter
authors.initials: P
authors.lastname: Vickerman
authors.forename: Charlotte H
authors.initials: CH
authors.lastname: Watts
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000191:economics; D019380:Anti-HIV Agents / Q000191:economics*; D002944:Circumcision, Male; D003362:Cost-Benefit Analysis; D005260:Female; D005544:Forecasting; D015658:HIV Infections / Q000191:economics / Q000453:epidemiology / Q000517:prevention & control*; D006679:HIV Seropositivity / Q000191:economics; D006558:Herpes Genitalis / Q000517:prevention & control*; D018258:Herpesvirus 2, Human; D006801:Humans; D015994:Incidence; D008297:Male; D018803:Models, Economic; D063065:Organophosphonates / Q000191:economics*; D015995:Prevalence; D013019:South Africa / Q000453:epidemiology; D000068698:Tenofovir
chemical_list: D019380:Anti-HIV Agents; D063065:Organophosphonates; D000068698:Tenofovir; D000225:Adenine