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Can enhanced screening of men with a history of prior syphilis infection stem the epidemic in men who have sex with men? A mathematical modelling study
  1. Ashleigh R Tuite1,
  2. Souradet Shaw2,3,
  3. Joss N Reimer3,
  4. Craig P Ross3,
  5. David N Fisman4,5,6,
  6. Sharmistha Mishra4,5,6,7
  1. 1 T H Chan School of Public Health, Harvard University, Boston, Massachusetts, USA
  2. 2 Department of Community Health Sciences, University of Manitoba, Winnipeg, Canada
  3. 3 Winnipeg Regional Health Authority, Winnipeg, Manitoba, Canada
  4. 4 Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, Canada
  5. 5 Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
  6. 6 Institute of Medical Sciences, University of Toronto, Toronto, Canada
  7. 7 Centre for Urban Health Solutions, Li Ka Shing Knowledge Institute, University of Toronto, Toronto, Canada
  1. Correspondence to Dr Sharmistha Mishra, University of Toronto, Room 363, Li Ka Shing Knowledge Institute, 30 Bond Street, Toronto, ON M5B 1W8, Canada; sharmistha.mishra{at}


Objectives The aim of this study is to determine the transmission impact of using prior syphilis infection to guide a focused syphilis screening intervention among men who have sex with men (MSM).

Methods We parameterised a deterministic model of syphilis transmission in MSM to reflect the 2011–2015 syphilis outbreak in Winnipeg, Canada. Enhanced screening of 75% of men with prior syphilis every 3 months (A) was compared with distributing equivalent number tests to all MSM (B) or those with the highest partner number (C). We compared early syphilis incidence, diagnoses and prevalence after 10 years, relative to a base case of 30% of MSM screened annually.

Results Strategy A was expected to avert 52% of incident infections, 44% of diagnosed cases and reduce early syphilis prevalence by 89%. Strategy B had the least impact. Strategy C was most effective, averting 59% of incident cases. When screening frequency was semiannual or annual, strategy A was the most effective.

Conclusions Enhanced screening of MSM with prior syphilis may efficiently reduce transmission, especially when identification of high-risk men via self-reported partner numbers or high-frequency screening is difficult to achieve.


Statistics from


  • Handling editor Jackie A Cassell

  • Contributors All authors participated in study conception and design and interpretation of results. AT built the model and performed the analyses. SS, JR and CR assisted with data acquisition. AT and SM drafted the manuscript, and all authors assisted with critical revision of the manuscript.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Model code is available upon request by contacting the corresponding author.

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