title: High HIV incidence in the postpartum period sustains vertical transmission in settings with generalized epidemics: a cohort study in Southern Mozambique.
abstract: BACKGROUND
  Acute infection with HIV in the postpartum period results in a high risk of vertical transmission through breastfeeding. A study was done to determine the HIV incidence rate and associated risk factors among postpartum women in Southern Mozambique, where HIV prevalence among pregnant women is 21%.
  
  
  METHODS
  A prospective cohort study was conducted in six rural health facilities in Gaza and Maputo provinces from March 2008 to July 2011. A total of 1221 women who were HIV-negative on testing at delivery or within two months postpartum were recruited and followed until 18 months postpartum. HIV testing, collection of dried blood spot samples and administration of a structured questionnaire to women were performed every three months. Infant testing by DNA-PCR was done as soon as possible after identification of a new infection in women. HIV incidence was estimated, and potential risk factors at baseline were compared using Poisson regression.
  
  
  RESULTS
  Data from 957 women were analyzed with follow-up after the enrolment visit, with a median follow-up of 18.2 months. The HIV incidence in postpartum women is estimated at 3.20/100 women-years (95% CI: 2.30-4.46), with the highest rate among 18- to 19-year-olds (4.92 per 100 women-years; 95% CI: 2.65-9.15). Of the new infections, 14 (34%) were identified during the first six months postpartum, 11 (27%) between 6 and 12 months and 16 (39%) between 12 and 18 months postpartum. Risk factors for incident HIV infection include young age, low number of children, higher education level of the woman's partner and having had sex with someone other than one's partner. The vertical transmission was 21% (95% CI: 5-36) among newly infected women.
  
  
  CONCLUSIONS
  Incidence of HIV is high among breastfeeding women in Southern Mozambique, contributing to increasing numbers of HIV-infected infants. Comprehensive primary prevention strategies targeting women of reproductive age, particularly pregnant and postpartum women and their partners, will be crucial for the elimination of paediatric AIDS in Africa.
authors.affiliation: Elizabeth Glaser Pediatric AIDS Foundation, Maputo, Mozambique; carolineds11@gmail.com.
authors.forename: Caroline
authors.initials: C
authors.lastname: De Schacht
authors.affiliation: Instituto Nacional de Saúde, Ministry of Health, Maputo, Mozambique.
authors.forename: Nédio
authors.initials: N
authors.lastname: Mabunda
authors.affiliation: Biology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil;
authors.forename: Orlando C
authors.initials: OC
authors.lastname: Ferreira
authors.affiliation: Instituto Nacional de Saúde, Ministry of Health, Maputo, Mozambique.
authors.forename: Nália
authors.initials: N
authors.lastname: Ismael
authors.affiliation: Provincial Health Directorate Gaza, Xai-Xai, Mozambique.
authors.forename: Nurbai
authors.initials: N
authors.lastname: Calú
authors.affiliation: Provincial Health Directorate Maputo, Matola, Mozambique.
authors.forename: Iolanda
authors.initials: I
authors.lastname: Santos
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health and Health Services, The George Washington University, Washington DC, USA.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Hoffman
authors.affiliation: Elizabeth Glaser Pediatric AIDS Foundation, Maputo, Mozambique.
authors.forename: Catharina
authors.initials: C
authors.lastname: Alons
authors.affiliation: Elizabeth Glaser Pediatric AIDS Foundation, Maputo, Mozambique; Department of Epidemiology and Biostatistics, School of Public Health and Health Services, The George Washington University, Washington DC, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Guay
authors.affiliation: Instituto Nacional de Saúde, Ministry of Health, Maputo, Mozambique.
authors.forename: Ilesh V
authors.initials: IV
authors.lastname: Jani
mesh_terms: D000293:Adolescent; D005260:Female; D015658:HIV Infections / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D018445:Infectious Disease Transmission, Vertical / Q000706:statistics & numerical data*; D009073:Mozambique / Q000453:epidemiology; D049590:Postpartum Period; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: HIV; Mozambique; PMTCT; breastfeeding; elimination paediatric HIV; incidence