一個大型的多中心臨床試驗 (HPTN052) 於2011年發表研究結論，假如治療中的愛滋病患者能保持病毒載量低水平，他們傳播愛滋病予性伴侶的機會是十分輕微的。這些結論促使利用病毒載量數據去形容愛滋病流行概况及評估高效抗逆轉錄病毒療法 (HAART) 干預策略對流行概况的影響。本研究旨在應用社區病毒載量去模擬香港愛滋病流行概况。 / 本研究收集了香港兩間主要愛滋病專科裡愛滋病患者縱向臨床數據，這些匿名的數據根據美國疾病預防控制中心所提議的人群病毒載量框架整合成流行病數據。其中社區、護理群及監測群病毒載量的計算是為了描述愛滋病流行概況，而新創的全社區病毒載量是用於估計社區裡確診與尚未確診的愛滋病感染者的集體病毒載量。香港未來愛滋病流行概況則利用決定性倉室模型模擬。異性模型透過性別分成兩個 (男女) 有聯繫的小模型，同性模型則用系統進化分析的近鄰結合法去劃分成16個獨立的小模型。除了基於現有情況模擬概況，治療、測試和混合干預策略以及外來感染的影響也被模擬。 / 從4362個病患中，一共收集了76,350CD4、64,412病毒載量和1042基因序列的回顧數據 (1985-2012)。當中有83%病患是男性、72%是中國人、89%是透過性接觸感染、74%曾經接受治療。能達到低病毒載量的病患百分比由1997年11%升至2012年76%，與HAART的推行情況方向一致。全社區病毒載量所顯示的上升趨勢於異性群和同性群中較其他病毒載量指標早五年出現。於2010-2020，異性群的愛滋病流行概況將維持不變，而同性群的流行概況將穩步上升但不是指數上升。干預策略中，以混合干預加上高治療保留率的策略對同性和異性群最有效，但增加重點測試對異性群比較可行，因為它舒緩了診斷延誤。另外，外來感染會影響干預策略的成效。 / 假如沒有包含病毒載量因素、外來感染和劃分模型，推測結果會高估流行概況，而治療覆蓋率的影響也不能被反映。基於人群病毒載量的重要性，定期收集所有專科的病毒載量數據並加以整合應該成為監測的一部份。這對於有廣泛治療覆蓋率的香港去研究流行概況是十分重要。 / Introduction: In 2011, a large multicentre trial (HPTN052) concluded that HIV+ persons on treatment with suppressed viral load (SVL) have minimal risk of virus transmission to their seronegative partners through sexual intercourse. These results provided evidence for the epidemiological use of viral load data to describe the HIV epidemics and assess impacts of treatment interventions. This study aims at modelling the HIV epidemic in Hong Kong by incorporating population-level viral load measures. / Methods: Longitudinal clinical data of patients attending two major HIV specialist services in Hong Kong were collected. The anonymized data were combined, adjusted and incorporated in an epidemiologic dataset in accordance with the CDC framework of viral load measures at population level. Specifically, community, in-care and monitored viral load were calculated to describe the HIV epidemic. Full community viral load, a new measure, was developed to infer the viral load burden of both diagnosed and undiagnosed individuals in the community. The HIV epidemic was then projected in a deterministic compartmental model. Gender was used to divide heterosexual model into two interrelated sub-models, while phylogenetic analysis (neighbour-joining tree) was applied to divide men-who-have-sex-with-men (MSM) model into 16 independent sub-models. Intervention scenarios of treatment coverage, testing coverage and retention expansion, and influence of non-local infection were projected and compared by modelling. / Results: A total of 76,350 CD4 and 64,412 viral load measurements of 4362 patients, and 1042 sequences were collected retrospectively (1985-2012). Among the patients included, 89% had acquired infection through sexual intercourse, and 74% had been started on highly active antiretroviral therapy (HAART). From viral load perspective, the proportion of patients in care with SVL (≤500copies/mL) increased sharply from 11% in 1997 to 76% in 2012, coinciding with the implementation of HAART. The growth curve of full community viral load was 5 years ahead of other viral load measures of heterosexuals and MSM. In 2010-2020, the HIV epidemic in heterosexuals would neither grow nor die down while the epidemic in MSM would continue to grow steadily but not exponentially. Among scenarios examined, test-and-treat intervention with high retention rate would be the most effective strategy for controlling the MSM and heterosexual epidemic. However, increasing the HIV testing rate for high risk people would be more feasible and impactful for the heterosexual, as a result of the early detection of HIV which would otherwise become late diagnoses. Non-local infection would affect the impact of interventions on epidemic control. / Conclusion: Without the inclusion of viral load measures, non-local infection and model delineation by subpopulations, epidemiologic projection results could be overestimated. Also, the impacts of treatment coverage on epidemic cannot be reflected if viral load measure is not included for describing epidemic growth. Acknowledging the importance of viral load measure, regular collection and aggregation of viral load measurements from all HIV clinics is recommended to form part of the HIV surveillance system. Such provision is important for studying HIV epidemiology descriptively and analytically in Hong Kong where coverage of HIV care is relatively extensive. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wong, Ngai Sze. / Thesis (Ph.D.) Chinese University of Hong Kong, 2015. / Includes bibliographical references (leaves 204-219). / Abstracts also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_1202925 |
| Date | January 2015 |
| Contributors | Wong, Ngai Sze (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, ii-vi, 285 leaves) : illustrations (some color), computer, online resource |
| Coverage | China, 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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