Search

Background: The Australian HIV 'partnership model' brings together government, community, clinicians and researchers across multiple disciplines including social, epidemiological, surveillance, and modelling to work together to inform each other on the best public health responses. This same model was used to establish the National Syphilis Action Plan (NSAP) in response to a resurgent syphilis epidemic among gay men. Methods: We combined mathematical modelling with quantitative and qualitative social research to explore the feasibility of different interventions (partner reduction, increased condom use, increased testing frequency, mass treatment, improved partner notification, and chemoprophylaxis) to reduce rates of syphilis. We conducted online surveys and focus groups to determine whether such interventions were likely to be acceptable to Australian gay men and we developed a mathematical transmission model that simulated sexually activity and transmission among a population of sexually active gay men to explore the potential epidemiological impact of each intervention. Results: The modelling demonstrated that changes in sexual behaviour (reducing sexual partner acquisition or increasing condom usage) are only likely to be effective if such changes are maintained indefinitely, and the social research data indicated such changes were not uniformly acceptable, particularly to gay men at higher risk and not as a long-term strategy. In contrast, increasing rates of testing for syphilis and partner notification were simulated to produce large reductions in syphilis infections and they were also broadly acceptable to all gay men. Use of chemoprophylaxis also appeared to be an effective strategy that had broad acceptance to gay men. Based on this interdisciplinary research and engagement with partners in the sector, target goals were set for Australia's NSAP. Conclusions: Our interdisciplinary approach demonstrated which interventions may be effective and acceptable in reducing syphilis infections within the target population. Interdisciplinary research can account for multiple factors to mutually inform public health programs. [ABSTRACT FROM AUTHOR]

The article presents a study which examined whether gay men would be willing to increase syphilis testing and partner notification, and assessed the possible epidemiological impact of these changes in the Australian population. It states that HIV-positive men were more likely to indicate that their frequency of syphilis testing was enough. The mathematical model showed that increasing testing rates would have a substantial effect on reducing rates of syphilis infection among gay men and partner notification would further reduce infections.

Abstract: A trial of the ALVAC-AIDSVAX HIV vaccine was recently found to be partially effective in preventing HIV transmission among study participants in Thailand. The success of this trial means that vaccination may become a viable intervention for the prevention of HIV infection in the medium-term future. Assuming that the vaccine has similar relative protective effectiveness per exposure event for reducing transmission among men who have sex with men (MSM) in high-income settings we investigated the potential population-level impact of rolling out such a vaccine among MSM in New South Wales, Australia. Using a detailed individual-based transmission model that simulates a population of sexually active MSM it was found that one-off intervention of 60% or 30% coverage of a vaccine with characteristics like the ALVAX-AIDSVAX vaccine would likely reduce the cumulative incidence of HIV by 9.6% and 5.1%, respectively, over a 10-year period. Due to the waning of vaccine efficacy, a booster vaccination could be required to maintain this reduction in incidence over the long term. If the previously vaccinated population is given a booster vaccine, with the same protection conferred as with the initial vaccination, every 5 years or every 2 years then the cumulative incidence over 10 years for 60% coverage could be reduced by 14.4% and 22.8%, respectively. Such a weak vaccine, with boosting, may be a potential intervention strategy for the prevention of HIV infection in MSM in high-income countries if further trials show boosting to be safe, acceptable, and cost-effective. However, the moderately low population-level impact suggests that a public health strategy involving such a vaccine should be supplemented with other biomedical and educational strategies. [Copyright &y& Elsevier]