title: Interventions to strengthen the HIV prevention cascade: a systematic review of reviews.
abstract: Much progress has been made in interventions to prevent HIV infection. However, development of evidence-informed prevention programmes that translate the efficacy of these strategies into population effect remain a challenge. In this systematic review, we map current evidence for HIV prevention against a new classification system, the HIV prevention cascade.
  
  
  
  We searched for systematic reviews on the effectiveness of HIV prevention interventions published in English from Jan 1, 1995, to July, 2015. From eligible reviews, we identified primary studies that assessed at least one of: HIV incidence, HIV prevalence, condom use, and uptake of HIV testing. We categorised interventions as those seeking to increase demand for HIV prevention, improve supply of HIV prevention methods, support adherence to prevention behaviours, or directly prevent HIV. For each specific intervention, we assigned a rating based on the number of randomised trials and the strength of evidence.
  
  
  
  From 88 eligible reviews, we identified 1964 primary studies, of which 292 were eligible for inclusion. Primary studies of direct prevention mechanisms showed strong evidence for the efficacy of pre-exposure prophylaxis (PrEP) and voluntary medical male circumcision. Evidence suggests that interventions to increase supply of prevention methods such as condoms or clean needles can be effective. Evidence arising from demand-side interventions and interventions to promote use of or adherence to prevention tools was less clear, with some strategies likely to be effective and others showing no effect. The quality of the evidence varied across categories.
  
  
  
  There is growing evidence to support a number of efficacious HIV prevention behaviours, products, and procedures. Translating this evidence into population impact will require interventions that strengthen demand for HIV prevention, supply of HIV prevention technologies, and use of and adherence to HIV prevention methods.
  
  
  
  Bill & Melinda Gates Foundation.
authors.affiliation: Department of Social and Environmental Health Research, London School of Hygiene & Tropical Medicine, London, UK; Centre for Evaluation, London School of Hygiene & Tropical Medicine, London, UK. Electronic address: shari.krishnaratne@lshtm.ac.uk.
authors.forename: Shari
authors.initials: S
authors.lastname: Krishnaratne
authors.affiliation: Department of Social and Environmental Health Research, London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Hensen
authors.affiliation: Department of Global Health, Emory University, Atlanta, GA, USA.
authors.forename: Jillian
authors.initials: J
authors.lastname: Cordes
authors.affiliation: Public Health and Epidemiology, School of Medicine, Nottingham University, Nottingham, UK.
authors.forename: Joanne
authors.initials: J
authors.lastname: Enstone
authors.affiliation: Department of Social and Environmental Health Research, London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: James R
authors.initials: JR
authors.lastname: Hargreaves
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology; D017280:Condoms; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control* / Q000523:psychology / Q000821:virology; D015497:HIV-1 / Q000502:physiology; D006801:Humans; D015994:Incidence; D008297:Male; D065129:Pre-Exposure Prophylaxis; D012107:Research Design