3rd International AIDS Society Conference on HIV Pathogenesis and Treatment


Rio de Janeiro - July 24 - 27, 2005

MODELLING THE IMPACT OF CASUAL AND REGULAR PARTNERSHIPS ON HIV INCIDENCE AMONG HOMOSEXUAL MEN IN AUSTRALIA

IAS Conf HIV Pathog Treat 2005 Jul 24-27;3rd: Abstract No. MoOa0103

Razali K.1, Mao L.2, Prestage G.1, Grulich A.1, Van de Ven P.2, Kippax S.2, Law M.1
1National Centre in HIV Epidemiology and Clinical Research, NSW, Australia, 2National Centre in HIV Social Research, NSW, Australia

INTRODUCTION: Data on the sexual practice of homosexual men in Australia have indicated that between 1996-2003, the relative proportions of these men engaging in unprotected anal intercourse (UAI) with regular partners (UAIR) has been higher than those with casual partners (UAIC). However, since 1996 the annual rate of increase in men engaging in UAIC has been greater than that for UAIR. The aim of this study is to assess the relative contributions of casual and regular partnerships to HIV incidence among homosexual men in Australia using a mathematical model.

METHODS: A mathematical model was developed of HIV transmission among homosexual men in Australia during 1995-2004, distinguishing unprotected anal intercourse between casual (UAIC) and regular (UAIR) partnerships. For 2004-2010, the effect of changes in risk levels for either casual or regular partnerships were compared with a null model of stable risk levels.

RESULTS: The models suggested that in 1995, about 40% of incident cases were attributed to UAIC, increasing to more than 65% in 2004 despite some reduction in risk behaviour among homosexual men with casual partners. From 2004, a stable risk level resulted in a plateau of about 400 cases per year. A 10% annual UAIC increase resulted in a 61% increase in incidence by 2010, compared to a 27% increase for a similar increase in UAIR. Conversely, a 10% annual decrease in UAIC resulted in a 38% drop in incidence compared to 20% for UAIR.

CONCLUSIONS: The models suggest that since 1995, there is an increase in the contribution of casual partnerships in HIV incidence. Continued UAIC increases would result in an increased proportion of incident cases attributable to casual partnerships, and a dramatic increase in overall HIV incidence, much more than that expected from a similar UAIR increase.

Acrobat ReaderDownload PDF of this abstract.

Power Point PresentationDownload Power Point Presentation.

050724
MoOa0103
Dynamics of the HIV epidemic

Copyright © 2005 - International AIDS Society (IAS). All information and content relating to the abstracts from the 3rd International AIDS Society Conference on HIV Pathogenesis and Treatment, such as text, graphics, logos, button icons, images, audio clips, and software is protected by copyright. Permission is hereby granted for the non-commercial use or reproduction of the information on this web site, provided that the use of such information is accompanied by an acknowledgement that IAS is the source of the information and the name of the author of the article.

AEGiS is made possible through unrestricted funding from Boehringer Ingelheim, Bridgestone/Firestone Charitable Trust, Bristol-Myers Squibb Company, Elton John AIDS Foundation, the National Library of Medicine, and donations from users like you. Always watch for outdated information. This article first appeared in 2005. This material is designed to support, not replace, the relationship that exists between you and your doctor.

AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.

Copyright ©1980, 2005. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content. Permission is hereby granted for the non-commercial use or reproduction of the information herein, provided that the use of such information is accompanied by an acknowledgement that IAS is the source of the information and the name of the author of the article.