Preferences on the Uptake and Completion of One- or Three-Dose Regimen of Benzathine Penicillin G Injection for the Treatment of Late Latent Syphilis 


2023 - 2024.

Project status 

Nearing completion. 

Chief Investigators

Professor Jonine Jancey (Curtin University)


Associate Professor Richard Norman (Curtin University), Associate Professor Jason Ong (Monash University), Dr Daniel Vujcich (Curtin University), Dr Rochelle Tobin (Curtin University), Dr Nang Nge Nge Phoo (Curtin University).

Brief overview

Currently, late latent syphilis is treated with three doses of penicillin injection administered at one-week intervals. However, treatment completion is low. Early research findings suggest that a single high dose of penicillin may be just as effective as the current three dose regimen and increase treatment completion. This study aims to understand what factors influence syphilis treatment completion and patient treatment preferences. The core components of the project are:

  1. A systematic review examining barriers to, and enablers of late latent syphilis treatment completion under the three-dose BPG regimen.
  2. An online survey to explore Australian sexual health clinicians’ perspectives of barriers to, and enablers of, late latent syphilis treatment completion under the current three-dose BPG regimen; and training needs for healthcare providers and service resource implications associated with the potential introduction of a single-dose treatment regimen.
  3. A discrete choice experiment to determine which attribute levels of either a three-dose or single-dose BPG regimen for treating late latent syphilis were preferred, and which attributes were deemed the most important by a sample of Australian gay, bisexual, and other men who have sex with men.

Project Outputs and Impacts

This study aims to understand what influences treatment completion of the current three-dose regimen and treatment preferences related to the potential new single-dose regimen for Australian gay, bisexual, and other men who have sex with men. The findings will help to understand the feasibility and acceptability of the proposed new treatment plan, in the event that a clinical trial demonstrates pharmacokinetic equivalence.


Collaboration for Evidence, Research and Impact in Public Health (CERIPH). (2024). Late latent syphilis treatment: Clinician perspectives of the current three-dose benzathine penicillin G regimen and the implementation of a single-dose regimen. CERIPH, Curtin University: Bentley, Western Australia.

Tobin R, Roberts M, Phoo NNN, Manning L, Norman R, Eadie-Mirams E, et al. Factors influencing adult and adolescent completion of a three-dose regimen of benzathine penicillin G for the treatment of late syphilis: A mixed methods systematic review. Manuscript submitted for publication.