title: The prevalence and incidence of HIV-1 infection and syphilis in a cohort of police officers in Dar es Salaam, Tanzania: a potential population for HIV vaccine trials.
abstract: OBJECTIVE
  To assess the suitability of a cohort of police officers in Dar es Salaam for HIV vaccine trials by determining the prevalence and incidence of HIV-1 infection, active syphilis and their associated factors.
  
  
  METHODS
  An open cohort study of police officers in Dar es Salaam, Tanzania.
  
  
  METHODS
  Recruitment of police officers began in 1994. A standardized questionnaire was completed at enrolment and subsequent visits. HIV antibodies were determined using two consecutive enzyme-linked immunosorbent assays. Samples repeatedly discordant on the two tests were tested by a Western blot assay. Treponema pallidum antibodies were first determined by Venereal Disease Research Laboratory (VDRL) test and reactive sera were confirmed by Treponema pallidum hemagglutination test.
  
  
  RESULTS
  At the end of 1996 a total of 2850 police officers had been recruited of whom 2733 (96%) consented to be tested for HIV. The overall HIV-1 seroprevalence at recruitment was 13.8% (378 of 2733). Females had a significantly higher HIV-1 seroprevalence, 18.0% (55 of 306), as compared to males, 13.3% (323 of 2427), P< 0.05. From a total of 2215 married police officers, 585 (26.4%) responded to a question on extramarital sex within the previous 3 months of whom 36.2% (212 of 585) admitted to have had at least one extramarital sexual intercourse. Condoms were not used during these encounters by 178 of 212 (84.0%). As of 31st December 1998, among the 1524 males observed for 2553 person-years (PYAR), 50 had seroconverted and among 200 females observed for 357 PYAR, eight had seroconverted. The overall crude HIV-1 incidence was thus 19.9/1000 PYAR; 19.6 and 22.4/1000 PYAR for males and females, respectively. The overall prevalence and incidence of active syphilis were 3.1% (88 of 2850) and 8.6/1000 PYAR (26 of 3149), respectively. Males had a higher prevalence of active syphilis, 84 of 2525 (3.3%) than females, five of 325 (1.5%), P = 0.09.
  
  
  CONCLUSIONS
  There was high risk sexual practice including low condom use in this cohort of police officers. The incidence and prevalence of HIV infection were high. Police officers in Dar es Salaam are therefore a potential population group for HIV vaccine evaluation.
authors.affiliation: Muhimbili University College of Health Sciences, Dar es Salaam, Tanzania.
authors.forename: M
authors.initials: M
authors.lastname: Bakari
authors.forename: E
authors.initials: E
authors.lastname: Lyamuya
authors.forename: F
authors.initials: F
authors.lastname: Mugusi
authors.forename: E
authors.initials: E
authors.lastname: Aris
authors.forename: S
authors.initials: S
authors.lastname: Chale
authors.forename: P
authors.initials: P
authors.lastname: Magao
authors.forename: R
authors.initials: R
authors.lastname: Jossiah
authors.forename: M
authors.initials: M
authors.lastname: Janabi
authors.forename: A
authors.initials: A
authors.lastname: Swai
authors.forename: N
authors.initials: N
authors.lastname: Pallangyo
authors.forename: E
authors.initials: E
authors.lastname: Sandström
authors.forename: F
authors.initials: F
authors.lastname: Mhalu
authors.forename: G
authors.initials: G
authors.lastname: Biberfeld
authors.forename: K
authors.initials: K
authors.lastname: Pallangyo
mesh_terms: D016915:AIDS Vaccines / Q000627:therapeutic use*; D000293:Adolescent; D000328:Adult; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D003710:Demography; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000453:epidemiology* / Q000628:therapy; D015528:HIV Seroprevalence; D015497:HIV-1; D006801:Humans; D015994:Incidence; D008297:Male; D016495:Police; D011446:Prospective Studies; D012959:Socioeconomic Factors; D013587:Syphilis / Q000150:complications / Q000453:epidemiology; D013636:Tanzania / Q000453:epidemiology
chemical_list: D016915:AIDS Vaccines