title: Timing of breast milk HIV-1 transmission: a meta-analysis.
abstract: OBJECTIVE
  To define the frequency and timing of breast milk transmission of HIV-1.
  
  
  METHODS
  Meta-analysis of data abstracted from published literature.
  
  
  METHODS
  Participants in prospective cohort studies of MTCT of HIV-1. Cohorts were separated on the basis of breast feeding duration.
  
  
  METHODS
  None.
  
  
  METHODS
  HIV-1 transmission rates.
  
  
  RESULTS
  Two thousand three hundred and seventy five HIV-1 infected women and their infants, 499 of whom breast fed, the estimated risk of breast milk HIV-1 transmission was 16% (95% CI: 9, 22%). Among breastfeeding infants, forty seven per cent of HIV-1 infections were attributable to breast feeding. Breast milk transmission risk was 21% (95% CI: 10, 33%) in cohorts with mean/median duration of breast feeding > or = 3 months and 13% (95% CI: 4, 21%) in cohorts with median duration of breast feeding < 2 months. In a separate analysis of 702 infants with prolonged duration of breast feeding, the risk of late postnatal transmission (infection occurring later than three to six months of age) was four per cent (95% CI 2, 5%).
  
  
  CONCLUSIONS
  This analysis suggests that breast milk transmission of HIV-1 is substantial and continues throughout the postnatal period. Early cessation of breast feeding at six months would avert some but not most infant HIV-1 infections due to breast feeding. While recently published studies showing some effectiveness of antiretrovirals early during the breast feeding period are encouraging, prevention of breast milk HIV-1 transmission needs to remain a high research priority.
authors.affiliation: Departments of Medicine, Epidemiology, and Biostatistics, University of Washington, Seattle, Washington 98195, USA.
authors.forename: G C
authors.initials: GC
authors.lastname: John
authors.forename: B A
authors.initials: BA
authors.lastname: Richardson
authors.forename: R W
authors.initials: RW
authors.lastname: Nduati
authors.forename: D
authors.initials: D
authors.lastname: Mbori-Ngacha
authors.forename: J K
authors.initials: JK
authors.lastname: Kreiss
mesh_terms: D001942:Breast Feeding / Q000706:statistics & numerical data*; D005260:Female; D015658:HIV Infections / Q000175:diagnosis / Q000517:prevention & control / Q000635:transmission*; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control / Q000706:statistics & numerical data*; D008895:Milk, Human / Q000821:virology*; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D011645:Puerperal Infection / Q000175:diagnosis / Q000517:prevention & control / Q000635:transmission*; D012307:Risk Factors; D013997:Time Factors