title: International multicentre pooled analysis of late postnatal mother-to-child transmission of HIV-1 infection. Ghent International Working Group on Mother-to-Child Transmission of HIV.
abstract: BACKGROUND
  An understanding of the risk and timing of mother-to-child transmission of HIV-1 in the postnatal period is important for the development of public-health strategies. We aimed to estimate the rate and timing of late postnatal transmission of HIV-1.
  
  
  METHODS
  We did an international multicentre pooled analysis of individual data from prospective cohort studies of children followed-up from birth born to HIV-1-infected mothers. We enrolled all uninfected children confirmed by HIV-1-DNA PCR, HIV-1 serology, or both. Late postnatal transmission was taken to have occurred if a child later became infected. We calculated duration of follow-up for non-infected children from the time of negative diagnosis to the date of the last laboratory follow-up, or for infected children to the mid-point between the date of last negative and first positive results. We stratified the analysis for breastfeeding.
  
  
  RESULTS
  Less than 5% of the 2807 children in four studies from industrialised countries (USA, Switzerland, France, and Europe) were breastfed and no HIV-1 infection was diagnosed. By contrast, late postnatal transmission occurred in 49 (5%) of 902 children in four cohorts from developing countries, in which breastfeeding was the norm (Rwanda [Butare and Kigali], Ivory Coast, Kenya), with an overall estimated risk of 3.2 per 100 child-years of breastfeeding follow-up (95% CI 3.1-3.8), with similar estimates in individual studies (p=0.10). Exact information on timing of infection and duration of breastfeeding was available for 20 of the 49 children with late postnatal transmission. We took transmission to have occurred midway between last negative and first positive HIV-1 tests. If breastfeeding had stopped at age 4 months transmission would have occurred in no infants, and in three if it had stopped at 6 months.
  
  
  CONCLUSIONS
  Risk of late postnatal transmission is consistently shown to be substantial for breastfed children born to HIV-1-positive mothers. This risk should be balanced against the effect of early weaning on infant mortality and morbidity and maternal fertility.
authors.affiliation: Unité INSERM 330, Université Victor Segalen Bordeaux 2, France. valeriane.leroy@dim.u-bordeaux2.fr
authors.forename: V
authors.initials: V
authors.lastname: Leroy
authors.forename: M L
authors.initials: ML
authors.lastname: Newell
authors.forename: F
authors.initials: F
authors.lastname: Dabis
authors.forename: C
authors.initials: C
authors.lastname: Peckham
authors.forename: P
authors.initials: P
authors.lastname: Van de Perre
authors.forename: M
authors.initials: M
authors.lastname: Bulterys
authors.forename: C
authors.initials: C
authors.lastname: Kind
authors.forename: R J
authors.initials: RJ
authors.lastname: Simonds
authors.forename: S
authors.initials: S
authors.lastname: Wiktor
authors.forename: P
authors.initials: P
authors.lastname: Msellati
mesh_terms: D015153:Blotting, Western; D001942:Breast Feeding; D015331:Cohort Studies; D019049:Developed Countries; D003906:Developing Countries; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission*; D015497:HIV-1; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D016133:Polymerase Chain Reaction; D012307:Risk Factors; D013997:Time Factors