title: Chemoprophylaxis is likely to be acceptable and could mitigate syphilis epidemics among populations of gay men.
abstract: BACKGROUND
  Over the last decade, syphilis epidemics have resurged around the world, particularly among gay men. An innovative public health response could be the use of chemoprophylaxis. We sought out to determine the acceptability of syphilis chemoprophylaxis and its likely population effectiveness if it were adopted.
  
  
  METHODS
  We conducted a mixed-methods study. An online survey (n = 2095 participants) and focus groups (n = 23 participants) were conducted to determine whether syphilis chemoprophylaxis is likely to be acceptable to gay men in Australia. We also developed an individual-based mathematical model that simulated a population of gay men, to explore the potential impact of introducing chemoprophylaxis.
  
  
  RESULTS
  Of the 2095 gay men surveyed, 52.7% (95% confidence interval, 50.6%-54.8%) indicated that they would be very likely or slightly likely to use chemoprophylaxis to reduce their chance of acquiring syphilis, increasing to 75.8% (95% confidence interval, 74.0%-77.6%) if chemoprophylaxis would help reduce infections in the gay community. In this model, 70% use-effectiveness of chemoprophylaxis used by 50% of gay men is expected to reduce the number of syphilis cases by ∼50% after 12 months and 85% after 10 years. The majority of the prevention efforts can be gained by targeting subpopulations of men with higher sexual activity.
  
  
  CONCLUSIONS
  Chemoprophylaxis offers promise as an acceptable and effective intervention for mitigating syphilis epidemics. The outcomes of a planned placebo-controlled syphilis chemoprophylaxis trial are eagerly anticipated.
authors.affiliation: National Centre in HIV Epidemiology and Clinical Research, The University of New South Wales, Sydney, Australia. Dwilson@nchecr.unsw.edu.au
authors.forename: David P
authors.initials: DP
authors.lastname: Wilson
authors.forename: Garrett P
authors.initials: GP
authors.lastname: Prestage
authors.forename: Richard T
authors.initials: RT
authors.lastname: Gray
authors.forename: Alexander
authors.initials: A
authors.lastname: Hoare
authors.forename: Pol
authors.initials: P
authors.lastname: McCann
authors.forename: Ian
authors.initials: I
authors.lastname: Down
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Guy
authors.forename: Fraser
authors.initials: F
authors.lastname: Drummond
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Klausner
authors.forename: Basil
authors.initials: B
authors.lastname: Donovan
authors.forename: John M
authors.initials: JM
authors.lastname: Kaldor
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D018890:Chemoprevention; D004318:Doxycycline / Q000627:therapeutic use*; D058872:Epidemics / Q000517:prevention & control* / Q000706:statistics & numerical data; D019538:Health Care Surveys; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010342:Patient Acceptance of Health Care; D012725:Sexual Behavior; D013587:Syphilis / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D055815:Young Adult
chemical_list: D004318:Doxycycline