title: Estimates of peripartum and postnatal mother-to-child transmission probabilities of HIV for use in Spectrum and other population-based models.
abstract: BACKGROUND
  The Global Plan Towards the Elimination of New HIV Infections among Children and Keeping Their Mothers Alive aims to reduce by 2015 the number of new infections in children, in 22 priority countries, by at least 90% from 2009 levels. Mathematical models, such as Spectrum, are used to estimate national and global trends of the number of infants infected through mother-to-child transmission (MTCT). However, other modelling exercises have also examined MTCT under different settings. MTCT probabilities applied in models to populations that are assumed to receive antiretroviral interventions need to reflect the most current risk estimates.
  
  
  METHODS
  The UNAIDS Reference Group on Estimates, Modelling and Projections held a consultation to review data on MTCT probabilities. Published literature, recent conferences and data from personal communications with principle investigators were reviewed. Based on available data, peripartum and postnatal transmission probabilities were estimated for different antiretroviral drug regimens and maternal CD4 levels including for women with incident infection.
  
  
  RESULTS
  Incident infections occurring during pregnancy are estimated to be associated with a 30% probability of MTCT; incident infections during breast feeding lead to a 28% probability of postnatal MTCT. The 2010 WHO recommended regimens (Options A or B) are estimated to be associated with a 2% peripartum transmission probability and 0.2% transmission probability per month of breast feeding. Peripartum and postnatal transmission probabilities were lowest for women who were taking antiretroviral therapy before the pregnancy namely 0.5% peripartum and 0.16% per month of breast feeding, respectively.
  
  
  CONCLUSIONS
  These updated probabilities of HIV transmission (applied to Spectrum in April 2011) will be used to estimate new child HIV infections and track progress towards the 2015 targets of the Global Plan.
authors.affiliation: Department of Maternal, Newborn, Child and Adolescent Health, World Health Organization, Avenue Appia 20, Geneva 1211, Switzerland. rollinsn@who.int
authors.forename: Nigel
authors.initials: N
authors.lastname: Rollins
authors.forename: Mary
authors.initials: M
authors.lastname: Mahy
authors.forename: Renaud
authors.initials: R
authors.lastname: Becquet
authors.forename: Louise
authors.initials: L
authors.lastname: Kuhn
authors.forename: Tracy
authors.initials: T
authors.lastname: Creek
authors.forename: Lynne
authors.initials: L
authors.lastname: Mofenson
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage; D018791:CD4 Lymphocyte Count; D004812:Epidemiologic Methods; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology / Q000635:transmission*; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D015233:Models, Statistical; D058725:Peripartum Period; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology
chemical_list: D019380:Anti-HIV Agents