Paul Van de Ven
University of New South Wales
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Featured researches published by Paul Van de Ven.
AIDS | 2001
Matthew Law; Garrett Prestage; Andrew E. Grulich; Paul Van de Ven; Susan Kippax
ObjectiveTo assess the competing effects on HIV incidence in homosexual men of the decreased infectiousness of men with HIV receiving effective combination antiretroviral treatments and homosexual men engaging in unprotected anal intercourse with increased numbers of partners (levels of unsafe sex). MethodsA mathematical model of HIV transmission in homosexual men was developed, based on the HIV epidemic in Australia in 1996, when effective antiretroviral treatments first became widely available. Uncertainties in parameters were modelled using 1000 simulations. The effect of treatments on decreasing infectiousness was randomly sampled with a median 10-fold decrease in infectiousness (range 100-fold to no decrease). Levels of unsafe sex were randomly sampled with a median 50% increase in unsafe sex (range 100% to no increase). The percentage change in HIV incidence after one year was obtained by comparison with a null model in which there was no decrease in infectiousness as a result of treatment and no change in unsafe sex. ResultsResults of the models suggested that whereas increased levels of unsafe sex were linearly associated with increases in HIV incidence, decreases in infectiousness because of treatments were non-linearly associated with decreases in HIV incidence. An assessment of the competing effects suggested that decreases in infectiousness of two-, five-, and 10-fold would be counterbalanced by increases in unsafe sex of approximately 40, 60 and 70%, respectively. ConclusionThese models suggest that apparently large decreases in infectiousness as a result of treatment could be counterbalanced in terms of new HIV infections by much more modest increases in unsafe sex.
AIDS | 2005
Paul Van de Ven; Limin Mao; Andrea S. Fogarty; Patrick Rawstorne; June Crawford; Garrett Prestage; Andrew E. Grulich; John M. Kaldor; Susan Kippax
Objective:To determine whether reporting that the HIV-positive partners viral load is undetectable rather than detectable is associated with unprotected anal intercourse (UAI) in HIV serodiscordant gay couples. Method:A cross-sectional study nested within two cohort studies, the Health in Men (HIM) cohort of HIV-negative men, from July 2001 to December 2003 and the Positive Health (PH) cohort of HIV-positive men, from February 2002 to August 2003. The study participants were 119 men in an HIV serodiscordant regular relationship of at least 6 months duration (45 HIV-negative men from HIM, 74 HIV-positive men from PH). The main outcome measure was the occurrence of UAI within the relationship in the previous 6 months. Results:Eighty-two men reported no UAI and 37 reported some UAI. Of couples in which the HIV-positive partners viral load was reported to be undetectable, 39.4% reported UAI compared with 20.8% of those where viral load was reported to be detectable (P = 0.04). In multivariate analysis, significant predictors of UAI were younger age [odds ratio (OR), 0.94; 95% confidence interval (CI), 0.87–1.00; P = 0.05], greater HIV optimism (OR, 4.98; 95% CI, 1.25–19.8; P = 0.02) and reported undetectable viral load (OR, 2.88; 95% CI, 1.13–7.37; P = 0.03). Conclusions:Most serodiscordant gay couples do not engage in any UAI. UAI within such relationships is significantly more likely to occur where the HIV-positive partner is reported to have undetectable viral load. UAI in HIV serodiscordant relationships is problematic even if viral load is undetectable because of unknown risk parameters, viral load variability and the possibility of drug-resistant strains of HIV.
Australian and New Zealand Journal of Public Health | 1998
Paul Van de Ven; Garrett Prestage; Judy French; Stephanie Knox; Susan Kippax
We examined differences over time in Sydney gay mens unprotected anal intercourse, particularly with a view to investigating any behavioural changes after the recent improvements in anti‐retroviral therapies. Trends in unprotected anal intercourse were monitored through the Sydney Gay Community Periodic (cross‐sectional) Surveys which were conducted at six‐monthly intervals between February 1996 and February 1998. Gay men (n=2,863) were recruited and self‐completed a short questionnaire at three gay venues and a sexual health clinic. There was a significant increase in unprotected anal intercourse with casual partners (but not with regular partners), applicable to both HIV positive and HIV negative men. Sexual practice was generally unrelated to ideas about recent advances in viral load testing and combination therapies.
Australian and New Zealand Journal of Public Health | 2005
Garrett Prestage; Limin Mao; Andrea S. Fogarty; Paul Van de Ven; Susan Kippax; June Crawford; Patrick Rawstorne; John M. Kaldor; Fengyi Jin; Andrew E. Grulich
Objective: To report changes in sexual behaviour among gay men in Sydney from 1986 to 2003.
Journal of Sex Research | 1997
Paul Van de Ven; Pamela Rodden; June Crawford; Susan Kippax
Our analysis draws a comparative profile of older homosexually active men. For an Australian national telephone survey (Project Male‐Call), 2,583 homosexually active men were interviewed. Questions about demographics, types of sexual partners, attachment to gay community, HIV/AIDS, and sexual practices were asked. About 10% (n = 256) of the Male‐Call men were over 49years. These older men were likely to live alone (52.7%), to be or have been married (62.9%), to have children (56.4%), and to have lived at their present address for more than five years (67.5%). Relatively few (12.4%) lived in gay areas, but a significant number (29.2%) lived in rural regions. They were generally less likely than younger men to have disclosed their sexual orientation (p < .00005). Although their attachment to gay community was quite strong, it was less than younger mens in terms of social attachment (p < .00001), cultural involvement (p < .001), and sexual involvement (p <. 00005). As a group, they were less likely to have ...
Aids and Behavior | 2006
June Crawford; Susan Kippax; Limin Mao; Paul Van de Ven; Garrett Prestage; Andrew E. Grulich; John M. Kaldor
In recent years, increases in both risk behavior and in seroconversion among homosexually active men have been noted in a number of parts of the world. Data were available from 903 HIV negative homosexual men regarding number of acts of unprotected anal intercourse (UAI), separated into receptive and insertive UAI, with and without ejaculation, with steady and with casual partners. Partners were classified according to serostatus as reported by respondents. Men (N = 325) reported 13,692 UAI acts, most of which were with steady partners, of whom most were reported to be HIV-negative. With HIV-positive partners, both steady and casual, and with casual partners of unknown serostatus, receptive UAI with ejaculation was relatively rare. Insertive UAI without ejaculation was relatively common with casual partners of unknown serostatus. Patterns of UAI suggest that risk of transmission may be greater with steady partners. Men appear to modify practice according to both the nature of the relationship (steady or casual) and (assumed) serostatus of partner.
Critical Public Health | 1998
Susan Kippax; Paul Van de Ven
Abstract This paper examines the epidemic of orthodoxy affecting the evaluation of current health promotion work. This has resulted in the privileging of certain methods, in particular, experimental method and the randomized control trial. Problems identified by public health researchers are discussed but the major focus of our critique concerns the ways in which the experimental method and, especially, the randomized control trial, assume that the audience of any health promotion message comprises a number of asocial individuals who occupy non-discursive space in ahistorical time. An alternative approach is advocated which focuses attention on the programme of health promotion and education rather than on any one individual health promotion initiative or intervention. Attention is also given to educational and health promotion practices; it is here, we argue, that some of the answers to ‘what works’ are to be sought. We illustrate our argument with reference to a number of recent Australian health promot...
Drug and Alcohol Review | 1999
Stephanie Knox; Susan Kippax; June Crawford; Garrett Prestage; Paul Van de Ven
This study investigated the prevalence of non-prescription and injecting drug use among a nonclinical sample of gay and homosexually active men and examined what distinguished men who had recently injected drugs from other gay men. Gay and homosexually active men from three cohort studies in Brisbane, Melbourne and Sydney, Australia (N = 1438) were interviewed between June 1995 and July 1996. Three-quarters of the men reported using drugs in the 6 months prior to interview and 10% had injected drugs in this period. It was concluded that drug use is normative among gay men in Australian cities. Recent drug use without injecting was associated with high socioeconomic status and gay community attachment. Men who had recently injected drugs were as attached to gay community as men who had used without injecting. Multivariate analysis found that injecting drugs was more common among younger men and men who were HIV positive. Socioeconomic differences between the men who had injected recently and other men were...
Journal of Acquired Immune Deficiency Syndromes | 2004
Mark S. Clements; Garrett Prestage; Andrew E. Grulich; Paul Van de Ven; Susan Kippax; Matthew Law
Background:Previous mathematical models have indicated that any decrease in HIV incidence in homosexual men due to decreased infectiousness from antiretroviral treatment (ARV) may be offset by modest increases in unsafe sex. The aims of this study were to assess the effects of ARV use and increasing unprotected anal intercourse with casual partners (UAIC) in homosexual men on HIV incidence during 1995–2001 and to project HIV incidence depending on trends in ARV use and UAIC. Methods:A mathematical model of HIV transmission among homosexual men in Australia was developed. HIV incidence during 1995–2001 was estimated assuming that 70% of men in whom HIV was diagnosed received ARVs and assuming a 10% annual increase in UAIC. For 2001–2006, scenarios included ARV levels remaining at 70% or declining to 50% by 2006, combined with UAIC levels remaining at the 2001 level or continuing to increase annually by 10%. Findings:The number of incident HIV cases per year was predicted to have declined during 1996–1998 due to the introduction of effective ARVs, with a slow increase during 1998–2001 due to increased levels of UAIC when use of therapies was fairly stable. From 2001, a continued increase in UAIC was predicted to lead to a rise in HIV incidence. A rise in UAIC combined with a moderate decline in ARV use could lead to a 50% increase in HIV incidence by 2006. Interpretation:These models suggest that widespread ARV use has had some effect in reducing HIV incidence among homosexual men in Australia. However, if current trends in UAIC and ARV use continue, a resurgent HIV epidemic is predicted.
Sexual Health | 2004
Fengyi Jin; Garrett Prestage; Cathy Pell; Basil Donovan; Paul Van de Ven; Susan Kippax; John M. Kaldor; Andrew E. Grulich
OBJECTIVES To determine the prevalence and incidence of hepatitis A (HAV) and B (HBV) infection and vaccination in HIV-negative homosexual men in Sydney, and associated risk factors. METHODS An open prospective cohort study was conducted among a community-based sample of HIV-negative homosexual men in Sydney in 2001-02. Participants underwent a face-to-face interview, regarding demographics, sexual behavioural risk factors and sexually transmitted infections, and blood samples were collected. They were followed annually. RESULTS Nine hundred and three men completed a baseline interview by the end of 2002. Among them, 68% were seropositive to hepatitis A. The seroprevalence of prior hepatitis B infection was 19%, and 53% had serological evidence of HBV vaccination. Younger men were much more likely to be seronegative, with 48% and 46% of <25-year-olds being seronegative to HAV and HBV respectively. In multivariate analysis HAV and HBV infection were associated with increasing age, greater number of lifetime sex partners and HBV infection was also associated with previous sexually transmitted infections. HAV vaccination was associated with increasing age, greater number of lifetime sex partners, overseas travel in the last year and self-reported anogenital warts. HBV vaccination was associated with higher occupational status, greater lifetime number of sex partners and previous sexually transmitted infections. CONCLUSION Substantial proportions of gay community-attached young homosexual men are still at risk of HAV and HBV infection. This study points to a need for vaccination strategies which ensure high levels of hepatitis A and B immunity in young sexually active gay men.