台灣HIV-1分子流行病學–HIV-1亞型與危險因子監測

Abstract

Objectived：The main purposes of this study were to surveillance the HIV transmission and try to prevent it in Taiwan. (1) For the subtype surveillance purpose, this study was try to investigate the distribution of HIV-1 subtypes among different high-risk groups、spread pathways and evolution time period in Taiwan. (2)For the prevention purpose, this study wish to develop the HIV-1 infection risk prediction model for IDUs by using the questionnaire of risk factor investigation. This risk prediction model would aim to be a tool for predict their probable risk of HIV infection and increase their self-awareness HIV-1 infection. Methods：The study population came from a Taiwan HIV-1 surveillance network which builded from 2004. This network established a database which included HIV-1 infection risk factor questionnaire collection and HIV-1 seropositive blood samples from IDUs of jails and HIV/AIDS Outpatient department of China medical university hospital in Taiwan annually. (1) About HIV-1subtype surveillance, we collected 2007-2009 HIV-1 seropositive blood samples from HIV-1 surveillance network. Their subtypes were examined by using DNA sequencing and phylogenetic analysis, and applyed coalescent theory, molecular clock analysis to estimated evolution rate and time of the most recent common ancestors (TMRCA). And, the risk factor characteristics of different subtypes were calculated by the biostatistic method. (2) Using 2004 to 2005 risk factor questionnaire database in HIV-1 surveillance network for building up HIV-1 infection risk prediction model for IDUs, we investigated risk factors of HIV-1 infection by case-control study. The risk prediction model was established by logistic regression, and odds ratios (ORs) for each risk factor were summed. Then, we used ROC curve (Receiver operating characteristic curve) to know HIV-1 risk threshold of IDUs. Next, we collected 2007 -2008 data of risk factor questionnaire database to validate the accuracy of this risk prediction model. Result：(1) HIV-1 subtype surveillance : HIV-1 subtype determined by phylogenetic analysis and nested multiplex PCR. After subtyping, we found three HIV-1 subtypes in our cases, including CRF07_BC, subtype B and CRF01_AE, most of these is CRF07_BC. CRF07_BC originated in 1993.6-1997.3 in China. TMRCA of CRF07_BC from southern, middle and northern were dated to 1998.3-2003.3, 2003.4-2004.4 and 2002.7-2004.3. In HIV-1 subtype and related HIV-1risk factor analysis showed, demographic and risk behavior factos among HIV-1subtype were differenct. (2) For risk factor prevention purpose: In the risk prediction model of IDUs, the significant variables among men were education, syringe sharing, heroin diluention sharing, and knowledge of AIDS- persons often had the venereal diseases, they easier had AIDS, and among women was syringe sharing. The risk threshold value of ORs in men is 7.435 (sensitivity: 0.96; specificity: 0.52). Because only one significant variable among women, the risk threshold value of ORs was not calculated. Finally, we compared with the sum of total ORs for each risk factor and the risk threshold of ORs, then, we could identify the risk of HIV infection. Furthermore, we collected questionnaire in 2007 ~ 2008, and tested this prediction model. The test result is : sensitivity – 72.2% ; specificity – 60.5%.