title: Updates to the spectrum model to estimate key HIV indicators for adults and children.
abstract: BACKGROUND
  The Spectrum program is used to estimate key HIV indicators for national programmes. The purpose of the study is to describe the key updates made to Spectrum in the last 2 years to produce the version used in the 2013 global estimates of HIV/AIDS.
  
  
  METHODS
  The United Nations Programme on HIV/AIDS (UNAIDS) Reference Group on Estimates, Models and Projections regularly reviews new data and information needs and recommends updates to the methodology and assumptions used in Spectrum. The latest data from surveys, census and special studies are used to estimate key parameter values for countries and regions.
  
  
  RESULTS
  Country-specific life tables prepared by the United National Population Division (UNPD) have been incorporated into Spectrum's demographic projections replacing the model life tables used previously. This update includes revised estimates of non-AIDS life expectancy. Incidence among all adults 15-49 years generated from curve fitting to surveillance and survey data is now split by age using incidence rate ratios derived from Analysing Longitudinal Population-based HIV/AIDS data on Africa Network data for generalized epidemics. Methods for estimating the number of AIDS orphans have been updated to include the changing effects of PMTCT and antiretroviral therapy programmes. Procedures for estimating the number of adults eligible for treatment have been updated to reflect the 2013 WHO guidelines. Program data on AIDS mortality has been used to estimate prevalence trends in Argentina, Brazil and Mexico for the 2013 estimates.
  
  
  CONCLUSIONS
  Spectrum was updated for the 2013 round of HIV estimates in order to support national programmes with improved methods and data to estimating national indicators.
authors.affiliation: aFutures Institute, Glastonbury, CT bUniversity of Massachusetts, Amherst, MA cUnited Nations Population Division, New York, New York, USA dDepartment of Population Studies, London School of Hygiene and Tropical Medicine, UK eUNAIDS, Geneva, Switzerland fUNAIDS, Panama City, Panama gMRC-UVRI, Entebbe Uganda hDepartment of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK and Karonga Prevention Study, Chilumba, Malawi iRakai Health Sciences Program, Uganda jThe Africa Centre for Health and population Studies, University of KwaZulu Natal, Somkhele, South Africa kFaculty of Medicine, School of Public Health, Imperial College, London lNational Institute for Medical Research, Mwanza, Tanzani, UK.
authors.forename: John
authors.initials: J
authors.lastname: Stover
authors.forename: Kirill
authors.initials: K
authors.lastname: Andreev
authors.forename: Emma
authors.initials: E
authors.lastname: Slaymaker
authors.forename: Chaitra
authors.initials: C
authors.lastname: Gopalappa
authors.forename: Keith
authors.initials: K
authors.lastname: Sabin
authors.forename: Claudia
authors.initials: C
authors.lastname: Velasquez
authors.forename: Jessica
authors.initials: J
authors.lastname: Nakiyingi-Miiro
authors.forename: Amelia
authors.initials: A
authors.lastname: Crampin
authors.forename: Tom
authors.initials: T
authors.lastname: Lutalo
authors.forename: Kobus
authors.initials: K
authors.lastname: Herbst
authors.forename: Simon
authors.initials: S
authors.lastname: Gregson
authors.forename: Mark
authors.initials: M
authors.lastname: Urassa
mesh_terms: D000293:Adolescent; D000328:Adult; D000349:Africa; D017677:Age Distribution; D001118:Argentina / Q000453:epidemiology; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004812:Epidemiologic Methods; D005260:Female; D006678:HIV; D015658:HIV Infections / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D011247:Pregnancy; D015995:Prevalence; D014480:United Nations; D055815:Young Adult