title: Efficacy of HIV Postexposure Prophylaxis: Systematic Review and Meta-analysis of Nonhuman Primate Studies.
abstract: BACKGROUND
  The efficacy of antiretrovirals as postexposure prophylaxis (PEP) to prevent viral acquisition was demonstrated in nonhuman primate models of human immunodeficiency virus (HIV) in the early 1990s. To complement the evidence base for efficacy of HIV PEP in humans, we systematically reviewed the published data on PEP efficacy across animal studies.
  
  
  METHODS
  PubMed, Web of Science, and Embase were searched from inception to 31 May 2014 for randomized and nonrandomized studies reporting seroconversions among uninfected animals exposed to HIV or simian immunodeficiency virus, irrespective of route of exposure. Seroconversion risk data were pooled using random-effects models, and associations explored through meta-regression.
  
  
  RESULTS
  Twenty-five studies (408 primates) were included for review. The risk of serconversion was 89% lower among animals exposed to PEP compared with those that did not receive PEP (odds ratio, 0.11 [95% confidence interval, .05-.23]). Heterogeneity was low (I(2) = 0.0%). In meta-regression, a significant association was found between timing of PEP and seroconversion and the use of tenofovir compared with other drugs.
  
  
  CONCLUSIONS
  This review provides further evidence of the protective benefit of PEP in preventing HIV acquisition, and the importance of initiating PEP as early as possible following virus exposure.
authors.affiliation: Department of HIV/AIDS, World Health Organization.
authors.forename: Cadi
authors.initials: C
authors.lastname: Irvine
authors.affiliation: Department of Mental Health and Psychiatry, University Hospitals of Geneva, Switzerland.
authors.forename: Kieren J
authors.initials: KJ
authors.lastname: Egan
authors.affiliation: Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom.
authors.forename: Zara
authors.initials: Z
authors.lastname: Shubber
authors.affiliation: California National Primate Research Center, University of California, Davis.
authors.forename: Koen K A
authors.initials: KK
authors.lastname: Van Rompay
authors.affiliation: Department of HIV/AIDS, World Health Organization.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Beanland
authors.affiliation: Department of HIV/AIDS, World Health Organization.
authors.forename: Nathan
authors.initials: N
authors.lastname: Ford
mesh_terms: D000818:Animals; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D004195:Disease Models, Animal; D015658:HIV Infections / Q000517:prevention & control* / Q000635:transmission; D006679:HIV Seropositivity; D006801:Humans; D008297:Male; D056990:Post-Exposure Prophylaxis; D011323:Primates; D012044:Regression Analysis; D016097:Simian Acquired Immunodeficiency Syndrome / Q000517:prevention & control* / Q000635:transmission; D015302:Simian Immunodeficiency Virus; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D019380:Anti-HIV Agents
keywords: HIV/AIDS; nonhuman primate; postexposure prophylaxis; transmission