title: Sexual partnership patterns in malawi: implications for HIV/STI transmission.
abstract: BACKGROUND
  Concurrent sexual partnerships are believed to play an important role in HIV transmission in sub-Saharan Africa, but the contributions of concurrency to HIV and sexually transmitted infection (STI) spread depend on the details of infectious periods and relationship patterns. To contribute to the understanding of sexual partnership patterns in this region, we estimated partnership lengths, temporal gaps between partners, and periods of overlap across partners at an STI clinic in Lilongwe, Malawi.
  
  
  METHODS
  Participants underwent physical examinations and HIV tests, and responded to questionnaires about demographics and risk behaviors, including detailed questions about a maximum of 3 sexual partners in the previous 2 months. We calculated partnership length as the time between the first and most recent sexual contact with a partner, and gap length as the time between the most recent contact with 1 partner and the first contact with the next. We defined concurrent and consecutive partnerships as gap length ≤0 days and gap length >0 days, respectively.
  
  
  RESULTS
  In the study population (n = 183), 86% reported 0 or 1 partner, 5% reported multiple consecutive partnerships, and 9% reported concurrency. The mean partnership length was 858 days (median = 176 days). Gaps between consecutive partnerships were short (mean = 21 days), and overlaps across concurrent partners tended to be long (mean = 246 days).
  
  
  CONCLUSIONS
  Multiple sexual partnerships were uncommon, and partnerships were long on average. Among those reporting multiple recent partners, both long-term concurrency and narrowly spaced consecutive partnerships could present substantial risk for efficient transmission of HIV and classical STIs.
authors.affiliation: Department s of Epidemiology, The University of North Carolina, Chapel Hill, NC 27599-7030, USA. powersk@email.unc.edu
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Powers
authors.forename: Irving F
authors.initials: IF
authors.lastname: Hoffman
authors.forename: Azra C
authors.initials: AC
authors.lastname: Ghani
authors.forename: Mina C
authors.initials: MC
authors.lastname: Hosseinipour
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Pilcher
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Price
authors.forename: Audrey E
authors.initials: AE
authors.lastname: Pettifor
authors.forename: David A
authors.initials: DA
authors.lastname: Chilongozi
authors.forename: Francis E A
authors.initials: FE
authors.lastname: Martinson
authors.forename: Myron S
authors.initials: MS
authors.lastname: Cohen
authors.forename: William C
authors.initials: WC
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission*; D015497:HIV-1; D006801:Humans; D008295:Malawi; D008297:Male; D012309:Risk-Taking; D012725:Sexual Behavior; D012747:Sexual Partners; D012749:Sexually Transmitted Diseases / Q000453:epidemiology / Q000635:transmission*; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult