title: A longitudinal cohort study of HIV 'treatment as prevention' in gay, bisexual and other men who have sex with men: the Treatment with Antiretrovirals and their Impact on Positive And Negative men (TAIPAN) study protocol.
abstract: BACKGROUND
  Australia has increased coverage of antiretroviral treatment (ART) over the past decade, reaching 73% uptake in 2014. While ART reduces AIDS-related deaths, accumulating evidence suggests that it could also bolster prevention efforts by reducing the risk of HIV transmission ('treatment as prevention'). While promising, evidence of community-level impact of treatment as prevention on reducing HIV incidence among gay and bisexual men is limited. We describe a study protocol that aims to determine if scale up of testing and treatment for HIV leads to a reduction in community viraemia and, in turn, if this reduction is temporally associated with a reduction in HIV incidence among gay and bisexual men in Australia's two most populous states.
  
  
  METHODS
  Over the period 2009 to 2017, we will establish two cohorts making use of clinical and laboratory data electronically extracted retrospectively and prospectively from 73 health services and laboratories in the states of New South Wales and Victoria. The 'positive cohort' will consist of approximately 13,000 gay and bisexual men (>90% of all people living with HIV). The 'negative cohort' will consist of at least 40,000 HIV-negative gay and bisexual men (approximately half of the total population). Within the negative cohort we will use standard repeat-testing methods to calculate annual HIV incidence. Community prevalence of viraemia will be defined as the proportion of men with a viral load ≥200RNA copies/mm3, which will combine viral load data from the positive cohort and viraemia estimates among those with an undiagnosed HIV infection. Using regression analyses and adjusting for behavioural and demographic factors associated with infection, we will assess the temporal association between the community prevalence of viraemia and the incidence of HIV infection. Further analyses will make use of these cohorts to assess incidence and predictors of treatment initiation, repeat HIV testing, and viral suppression.
  
  
  CONCLUSIONS
  This study will provide important information on whether 'treatment as prevention' is associated with a reduction in HIV incidence at a community level among gay and bisexual men.
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.
authors.forename: D
authors.identifier: http://orcid.org/0000-0002-4116-4250
authors.initials: D
authors.lastname: Callander
authors.affiliation: Burnet Institute, Melbourne, VIC, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Stoové
authors.affiliation: St Vincent's Hospital, Sydney, NSW, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Carr
authors.affiliation: Monash University, Melbourne, VIC, Australia.|Alfred Hospital, Melbourne, VIC, Australia.
authors.forename: J F
authors.initials: JF
authors.lastname: Hoy
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Petoumenos
authors.affiliation: Burnet Institute, Melbourne, VIC, Australia.|Alfred Hospital, Melbourne, VIC, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Hellard
authors.affiliation: Monash University, Melbourne, VIC, Australia.|Alfred Hospital, Melbourne, VIC, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Elliot
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.|RPA Sexual Health, Community Health, Sydney Local Health District, Sydney, NSW, Australia.|Central Clinical School, The University of Sydney, Sydney, NSW, Australia.
authors.forename: D J
authors.initials: DJ
authors.lastname: Templeton
authors.affiliation: School of Public Health and Community Medicine, UNSW Australia, Sydney, NSW, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Liaw
authors.affiliation: Burnet Institute, Melbourne, VIC, Australia.
authors.forename: D P
authors.initials: DP
authors.lastname: Wilson
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Grulich
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.
authors.forename: D A
authors.initials: DA
authors.lastname: Cooper
authors.affiliation: Monash University, Melbourne, VIC, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Pedrana
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.|Sydney Sexual Health Centre, Sydney Hospital, Sydney, NSW, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Donovan
authors.affiliation: Monash University, Melbourne, VIC, Australia.|Alfred Hospital, Melbourne, VIC, Australia.
authors.forename: J
authors.initials: J
authors.lastname: McMahon
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.|Australian Research Centre in Sex, Health and Society, La Trobe University, Melbourne, VIC, Australia.
authors.forename: G
authors.initials: G
authors.lastname: Prestage
authors.affiliation: Centre for Social Research in Health, UNSW Australia, Sydney, NSW, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Holt
authors.affiliation: Monash University, Melbourne, VIC, Australia.|Melbourne Sexual Health Centre, Melbourne, VIC, Australia.
authors.forename: C K
authors.initials: CK
authors.lastname: Fairley
authors.affiliation: ACON Northern Rivers, Lismore, NSW, Australia.
authors.forename: N
authors.initials: N
authors.lastname: McKellar-Stewart
authors.affiliation: Victorian AIDS Council, Melbourne, VIC, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Ruth
authors.affiliation: Burnet Institute, Melbourne, VIC, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Asselin
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Keen
authors.affiliation: PositiveLife New South Wales, Sydney, NSW, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Cooper
authors.affiliation: Living Positive Victoria, Melbourne, VIC, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Allan
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Kaldor
authors.affiliation: The Kirby Institute, UNSW Australia, Wallace Wurth Building, Sydney, NSW, 2052, Australia. rguy@kirby.unsw.edu.au.
authors.forename: R
authors.initials: R
authors.lastname: Guy
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D001315:Australia / Q000453:epidemiology; D001727:Bisexuality; D015331:Cohort Studies; D006678:HIV / Q000235:genetics / Q000302:isolation & purification; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology; D018451:Homosexuality, Male; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence; D012367:RNA, Viral / Q000097:blood; D012189:Retrospective Studies; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral
keywords: Cohort; Gay men; HIV; Treatment as prevention