In the past decade, the rising incidence of human immunodeficiency virus (HIV) in men who have sex with men (MSM) calls for targeted epidemiological investigations. However, the approach of most current epidemiological studies might be inadequate for characterising transmission risks of MSM, as they focus largely on the practice of risk behaviours in population context and have assumed a homogeneous distribution of such behaviours and their resultant risks in HIV transmission. A study investigating the networking pattern of MSM, in addition to their sexual behaviour, was therefore proposed to re-examine HIV epidemiology in Hong Kong and model HIV transmission dynamics. / Following literature review on network analyses conducted in MSM, it was found that the use of two-mode network data for constructing sexual affiliation network had not been widely applied. Such two-mode network approach could be more feasible in describing sexual structure of MSM, who are connected by their preferred social venues. To adopt this approach, a two-part study, composing a field survey and a modelling study, was performed. A cross-sectional questionnaire survey was conducted between January and April 2013 to obtain data about sex-networking venues and associated behavioural profiles of MSM in Hong Kong. Comparisons of networking patterns, risk behaviour and demographics between MSM in different networks, delineated by two-mode network analysis, were made. Based on the survey data and assumptions derived from other network-based and behavioural studies, HIV transmission dynamics was simulated by building a stochastic agent-based model. / In the field survey, a total of 932 respondents were recruited from physical venues (n=625), including nine bars and six saunas, and the Internet (n=307). The proportion of MSM using condom for every anal sex with casual partners met in physical venues was 66.6% (225/338), while that for partners met in the Internet was 62.6% (139/222). Only 51.5% (204/396) MSM always used condom while having anal sex with regular partners. Community detection by networks of social venues identified nine clusters of MSM from three network bases. The simulation model gave a median number of new HIV infections over a 5-year period at 83 per 1000 MSM. The median numbers of annual infections ranged between 14 and 20. In over 30% of MSM networked through the Internet, having regular sex partners or practising receptive anal sex, more than 50 infections out of 500 iterations could occur in the model simulation, suggesting their higher risk of HIV infection. / In conclusion, the modelling results suggested that HIV transmission in Hong Kong might have occurred largely between regular partners. The potential impact of local sex-networking pattern through social venues with casual partners on HIV transmission is relatively little and indirect. To prevent HIV from spreading into new networks, intervention shall be targeted at MSM having unprotected anal sex with regular partners and seeking casual partners in social venues, especially through the Internet. Network approach in HIV epidemiology, such as collection of network-based data from HIV-infected MSM as part of surveillance, and assessing the network configuration from time to time, shall also be considered. / 過去十年間，透過同性性行為感染愛滋病病毒的個案持續上升，令針對男男性接觸者的流行病學研究顯得重要。現時大部分相關研究都假設所涉行為和相應的傳染風險是平均分佈於研究人群中，採用這研究方法去了解男男性接觸者間的病毒傳播風險明顯有所不足。有鑑於此，本研究透過了解男男性接觸者的社交網絡模式及其風險行為，重新審視本地愛滋病病毒感染的流行病學狀況及設計相關模型，用以了解病毒的傳播及流行規律。 / 探討過往文獻發現，雖然二模網絡能勾劃出男男性接觸者與其結識性伴侶的社交場所間的關係，卻未被廣泛應用於流行病學研究。本研究採納二模網絡的分析方法，並分兩部分進行。實地調查部分於二零一三年一月至四月期間進行，透過問卷收集本港男男性接觸者結交性伴侶的場所及相關性行為等資料，並比較其網絡模式、風險行為及人口特徵。建模研究部分則是利用調查所得之數據及參考其他研究去建立模型，用以模擬愛滋病病毒的傳播規律。 / 問卷調查從九間酒吧、六間桑拿及互聯網中，招募了九百三十二位受訪者參與研究。受訪者中，每次肛交均使用安全套的比率因性伴侶的種類而異，比率介乎百分之五十二至六十七。透過分析三種社交場所的網絡結構，本港男男性接觸者社群共可分為九個群組。由模擬模型得知，五年間新增的愛滋病病毒感染個案為八十三宗（每千人計），而相應的年度感染數字則介乎十四至二十宗。從五百次模擬運算中，發現超過三成透過互聯網結識性伴侶或擁有固定性伴侶的男男性接觸者與及受體肛交者的感染次數多於五十次，顯示其較高的愛滋病病毒感染風險。 / 總括而言，研究發現本港愛滋病病毒的傳播多於固定性伴侶間發生。相反，透過本地社交場所結識非固定性伴侶的網絡模式只間接影響本港愛滋病病毒的散播。為有效預防愛滋病病毒散播，干預措施應針對有與固定伴侶進行不安全性行為及透過互聯網結識性伴侶的男男性接觸者，同時衛生部門亦可考慮將感染愛滋病病毒的男男性接觸者的網絡數據納入恆常監測及不時評估同志社群間的網絡結構。 / Poon, Chin Man. / Thesis Ph.D. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 112-121). / Abstracts and appendix B also in Chinese. / Title from PDF title page (viewed on 07, October, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_1291494 |
| Date | January 2015 |
| Contributors | Poon, Chin Man (author.), Lee, S. S. (Shui Shan) (thesis advisor.), Chinese University of Hong Kong Graduate School. Division of Public Health. (degree granting institution.) |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography, text |
| Format | electronic resource, electronic resource, remote, 1 online resource (xiii, 150 leaves) : illustrations (some color), computer, online resource |
| Coverage | China, Hong Kong, CHina, Hong Kong, Hong Kong |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-NoDerivatives 4.0 International" License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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