title: Deciphering the complex distribution of human immunodeficiency virus type 1 subtypes among different cohorts in Northern Tanzania.
abstract: BACKGROUND
  Increased understanding of the genetic diversity of HIV-1 is challenging but important in the development of an effective vaccine. We aimed to describe the distribution of HIV-1 subtypes in northern Tanzania among women enrolled in studies preparing for HIV-1 prevention trials (hospitality facility-worker cohorts), and among men and women in an open cohort demographic surveillance system (Kisesa cohort).
  
  
  METHODS
  The polymerase encompassing partial reverse transcriptase was sequenced and phylogenetic analysis performed and subtype determined. Questionnaires documented demographic data. We examined factors associated with subtype using multinomial logistic regression, adjusted for study, age, and sex.
  
  
  RESULTS
  Among 140 individuals (125 women and 15 men), subtype A1 predominated (54, 39%), followed by C (46, 33%), D (25, 18%) and unique recombinant forms (URFs) (15, 11%). There was weak evidence to suggest different subtype frequencies by study (for example, 18% URFs in the Kisesa cohort versus 5-9% in the hospitality facility-worker cohorts; adjusted relative-risk ratio (aRR) = 2.35 [95% CI 0.59,9.32]; global p = 0.09). Compared to men, women were less likely to have subtype D versus A (aRR = 0.12 [95% CI 0.02,0.76]; global p = 0.05). There was a trend to suggest lower relative risk of subtype D compared to A with older age (aRR = 0.44 [95% CI 0.23,0.85] per 10 years; global p = 0.05).
  
  
  CONCLUSIONS
  We observed multiple subtypes, confirming the complex genetic diversity of HIV-1 strains circulating in northern Tanzania, and found some differences between cohorts and by age and sex. This has important implications for vaccine design and development, providing opportunity to determine vaccine efficacy in diverse HIV-1 strains.
authors.affiliation: Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania ; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Harr F
authors.initials: HF
authors.lastname: Njai
authors.affiliation: Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania ; MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Ewings
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: Eric
authors.initials: E
authors.lastname: Lyimo
authors.affiliation: Laboratoire de Virologie, University of Montpellier, Montpellier, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Foulongne
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: Dhamira
authors.initials: D
authors.lastname: Ngerageza
authors.affiliation: Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: Aika
authors.initials: A
authors.lastname: Mongi
authors.affiliation: MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
authors.forename: Deogratius
authors.initials: D
authors.lastname: Ssemwanga
authors.affiliation: Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania ; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Aura
authors.initials: A
authors.lastname: Andreasen
authors.affiliation: Kilimanjaro Christian Medical Centre, Moshi, Tanzania.
authors.forename: Balthazar
authors.initials: B
authors.lastname: Nyombi
authors.affiliation: Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania ; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Tony
authors.initials: T
authors.lastname: Ao
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: Denna
authors.initials: D
authors.lastname: Michael
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: Mark
authors.initials: M
authors.lastname: Urassa
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom ; National Institute for Medical Research, Mwanza, Tanzania ; Kilimanjaro Christian Medical Centre, Moshi, Tanzania.
authors.forename: Jim
authors.initials: J
authors.lastname: Todd
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Basia
authors.initials: B
authors.lastname: Zaba
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: John
authors.initials: J
authors.lastname: Changalucha
authors.affiliation: MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Hayes
authors.affiliation: Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania ; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Saidi H
authors.initials: SH
authors.lastname: Kapiga
mesh_terms: D000328:Adult; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D015658:HIV Infections / Q000175:diagnosis / Q000821:virology*; D054303:HIV Reverse Transcriptase / Q000145:classification* / Q000235:genetics; D015497:HIV-1 / Q000145:classification* / Q000235:genetics; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D058889:Molecular Typing; D010802:Phylogeny; D013636:Tanzania
chemical_list: D054303:HIV Reverse Transcriptase