title: High HIV-1 incidence in young women masked by stable overall seroprevalence among childbearing women in Kinshasa, Zaïre: estimating incidence from serial seroprevalence data.
abstract: OBJECTIVE
  To describe the dynamics of the HIV-1 epidemic in childbearing women in Kinshasa, Zaïre, by estimating incidence from serial seroprevalence studies.
  
  
  METHODS
  In 1986 and 1989, 5937 and 4623 pregnant women, respectively, were screened for HIV-1 in Kinshasa. We estimated age-specific incidence from two seroprevalence surveys by using a birth-year cohort analysis and adjusting for differences in mortality and fertility between HIV-1-infected and uninfected women. Mortality and fertility data were measured in a cohort of women recruited from the survey in 1986 and followed until 1989.
  
  
  RESULTS
  While the overall HIV-1 seroprevalence changed little (5.8% in 1986 and 6.5% in 1989; P = 0.17), the prevalence increased in birth-year cohorts of women under 25 years of age in 1989 from 3.2 to 6.2% (P < 0.001), but decreased for women above 25 years of age from 6.9 to 6.7% (P = 0.7). In addition, new HIV infections between 1986 and 1989 were balanced by a higher mortality and lower fertility observed in HIV-infected women. After adjusting for these effects, we estimated an overall 3-year cumulative HIV-1 incidence of 2.8 per 100 uninfected women [95% confidence interval (CI), 1.4-4.2]. The highest incidence, 5.7 per 100 (95% CI, 3.5-8.0), was in women aged 20-24 years in 1989.
  
  
  CONCLUSIONS
  Despite an overall relatively stable HIV-1 prevalence in childbearing women in Kinshasa between 1986 and 1989, approximately 40% of all HIV-1 infections detected in the 1989 survey occurred between 1986 and 1989, and 60% occurred in women under 25 years of age in 1989.
authors.affiliation: Projet SIDA, Kinshasa, Zaïre.
authors.forename: V
authors.initials: V
authors.lastname: Batter
authors.forename: B
authors.initials: B
authors.lastname: Matela
authors.forename: M
authors.initials: M
authors.lastname: Nsuami
authors.forename: T
authors.initials: T
authors.lastname: Manzila
authors.forename: M
authors.initials: M
authors.lastname: Kamenga
authors.forename: F
authors.initials: F
authors.lastname: Behets
authors.forename: R W
authors.initials: RW
authors.lastname: Ryder
authors.forename: W L
authors.initials: WL
authors.lastname: Heyward
authors.forename: J M
authors.initials: JM
authors.lastname: Karon
authors.forename: M E
authors.initials: ME
authors.lastname: St Louis
mesh_terms: D000328:Adult; D015331:Cohort Studies; D015023:Democratic Republic of the Congo / Q000453:epidemiology; D005260:Female; D005298:Fertility; D015528:HIV Seroprevalence; D015497:HIV-1; D006801:Humans; D015994:Incidence; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology*