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We studied HIV rate in different age populations and whether there has been on-going new infections in Hong Kong by examining the age characteristics and their temporal trend of reported HIV infections. It was found that people in the age group 25-34 were worst hit by the local epidemic. Ageing cohort effect was not apparent for the age pattern of sexually-acquired infections reported from 1987 to 2000 with the annual median ages ranged from 31.5 to 36 years (regression coefficient -0.14 95% confidence interval 70.14 to 0.42 P=0.295). Similar temporal age patterns were observed for individual subgroups of homo-/bisexuals heterosexuals and female heterosexuals. The findings suggested the occurrence of new HIV infections over the years in Hong Kong despite maintenance of a low prevalence. Albeit capturing largely prevalent infections reported HIV/AIDS data could be tapped for understanding the evolving epidemic pattern to better evaluate and target current prevention programmes. (authors)

Three cohorts (n = 391) of final-year medical students in Hong Kong were evaluated on their preparedness to provide HIV care. Through a self-administered questionnaire, half (53%) were assessed to be better prepared and had a lower perceived risk of infection at work, though unwillingness to manage HIV patients was reported in a minority (4.6%). For a majority of medical students (72.8%), a specially-designed clinic attachment offered the only opportunity to come face-to-face with HIV patients for the first time. With continued improvement in treatment effectiveness, HIV/AIDS is evolving to become a new chronic disease in most societies. Curriculum development in HIV medicine remains a challenge in this HAART era.

Supplemental Digital Content is available in the text, In HIV-infected persons, age is negatively associated with optimal CD4 recovery following antiretroviral therapy. Our understanding of the situation in older adults, especially the middle-aged is, however, limited. We undertook to examine the latter's pattern of CD4/CD8 recovery following antiretroviral therapy. Retrospective clinical cohort data of HIV patients diagnosed between 1985 and 2014 in Hong Kong were collected. They were categorized by age at treatment initiation, viz., young adults (age 18–49), middle-aged (age 50–64), and elderly (≥65 years’ old). Predictors of immune recovery (CD4 count, CD8 count, CD4/CD8 ratio) over time were examined using multivariable linear generalized estimating equations. A total of 2754 patients (aged ≥18) have been on antiretroviral therapy, with baseline characteristics similar between middle-aged and the elderly. Late diagnosis, defined as progression to AIDS within 3 months of HIV diagnosis, was less common in middle-aged (odds ratio = 0.58, 95% confidence interval = 0.37–0.91). Among Chinese patients who have been on treatment for ≥4 years (n = 913), 80.6%, 14.6%, and 4.8% were young adults, middle-aged, and elderly respectively. Late treatment initiation, defined as AIDS diagnosis or CD4 count ≤100 cells/μL before treatment, was common in middle-aged and elderly, the former however had faster CD4 recovery (3.95 vs. 3.36 cells/μL/month), but slower CD8 decline (−1.76 vs. −4.34 cells/μL/month) and CD4/CD8 normalization (0.009 vs. 0.0101/month). As a transitional age group, the immune recovery of middle-aged patients lagged behind young adults largely because of late treatment initiation. Following adoption of early and non-CD4-guided treatment initiation, their long-term clinical outcome is expected to improve.

In 2009, a cross-sectional survey of 360 poultry workers in Hong Kong, China, showed that workers had inadequate levels of avian influenza (H5N1) risk knowledge, preventive behavior, and outbreak preparedness. The main barriers to preventive practices were low perceived benefits and interference with work. Poultry workers require occupation-specific health promotion.

Over half (58.4%) of 77 recently diagnosed Chinese HIV infected men having sex with men (MSM) had networked sex partners through Internet in the year prior to their infections. Internet using MSM were younger (29.6y vs 38.7y; t = -4.77, P

Background “Casual sex” is seldom as non-selective and random as it may sound. During each sexual encounter, people consciously and unconsciously seek their casual sex partners according to different attributes. Influential to a sexual network, research focusing on quantifying the effects of physical appearance on sexual network has been sparse. Methods We evaluated the application of Log odds score (LOD) to assess the mixing patterns of 326 men who have sex with men (MSM) in Hong Kong in their networking of casual sex partners by Body Image Type (BIT). This involved an analysis of 1,196 respondents-casual sex partner pairs. Seven BITs were used in the study: Bear, Chubby, Slender, Lean toned, Muscular, Average and Other. Results A hierarchical pattern was observed in the preference of MSM for casual sex partners by the latter's BIT. Overall, Muscular men were most preferred, followed by Lean toned while the least preferred was Slender, as illustrated by LOD going down along the hierarchy in the same direction. Marked avoidance was found between men who self-identified as Chubby and men of Other body type (within-group-LOD: 1.25–2.89; between-group-LOD

To explore the heterogeneity of CD4 responses following highly active antiretroviral therapy, the patterns of CD4 recovery of HIV-1-infected Chinese patients who have been on their first antiretroviral regimen for ≥5 years were analysed. The CD4 trajectories were traced, smoothed and differentiated into three defined profiles. Half (56.3%) were ‘satisfactory responders’, with CD4 gain of >100 cells/μL and a peak of >350 cells/μL, plateauing before the end of Year 5. Thirty-three (24.4%) were ‘continuing responders’ whose CD4 rise persisted at Year 4–5. The remaining 26 (19.3%) were ‘poor responders’. Presentation with AIDS before therapy was common not just among ‘poor’ but also paradoxically the ‘continuing’ responders. While a majority had responded well to antiretroviral therapy, older patients and those with AIDS diagnosis before initiation of therapy may never achieve a satisfactory level even with effective treatment. Categorization of HIV patients by their CD4 trajectory may support the prediction of immunological outcome over time, and ultimately inform treatment choices.

SummaryThe seasonality of influenza infections can be affected by virus subtypes, climate, and social networking in populations. While these factors are well known, their relative influences in specific age groups have not been fully investigated. During 2010–2011, patients aged 65 years and above with influenza virus infections were recruited from a regional hospital in Hong Kong. They were either residents of homes for the elderly (n=60) or living with their family (n=75). Two seasons were distinguished, the summer season of 2010 dominated by H3N2 and the winter season of 2011 dominated by H1N1. The patients’ clinical presentations and patterns of inter-personal connectivity were assessed. Overall, more elderly people living with their family were diagnosed with H1N1 compared to those in the homes for the elderly, and the former had visited a more diverse range of places 1 week prior to diagnosis. A higher proportion of patients living with family presented with lower respiratory tract symptoms, but these patients were less likely to have pre-existing chronic diseases. The results suggest that elderly patients infected during an influenza season could vary by virus subtype, which in turn is dependent on exposure locations and the pattern of social connectivity.

On the basis of results of testing of 212 peripheral blood samples from ethnic Chinese individuals in five age groups, ranging from birth to adulthood, by standardized flow cytometry techniques, we studied the maturational processes that are pertinent to monitoring the human immunodeficiency virus (HIV)-infected Chinese pediatric population. While the numbers of peripheral total white cells and percent lymphocytes declined from birth to adulthood, the percent CD3+T lymphocytes was steady among all age groups studied. The numbers of CD3+CD4+(T-helper) cells decreased markedly after the first year of life, followed by a slower decline afterward and then a slight increase before adulthood. The trend for CD3+CD8+(T-suppressor) cells, however, was an increase among individuals of all age ranges. The numbers of CD19+CD3−(B cells) increased only during the first year of life and then declined steadily, while natural killer (NK) cells showed the opposite pattern. Comparison of the results with those of studies done with a Caucasian population showed that both peripheral T-helper and T-suppressor cell numbers were low after the first year of life in the Chinese pediatric population in comparison with those in a Caucasian pediatric population. Lower B-cell counts and higher NK-cell counts were seen after the first year of life in the Chinese population than in the Caucasian population. It is important that for each HIV-infected population normative ranges of the lymphocyte subset be established to monitor HIV-infected pediatric patients.

This study assessed the usefulness of routine chest radiography for detecting active pulmonary tuberculosis in persons infected with human immunodeficiency virus (HIV) without suggestive symptoms in Hong Kong. Tuberculosis is common in this locality and tuberculosis/HIV co-infection has been a frequent and significant problem. Records of patients attending the largest HIV clinic were reviewed. Three hundred and eleven routine chest radiographs were performed among 191 HIV-infected patients with a total follow-up period of 792 person years. Of the 22 routine chest radiographs that had abnormalities in the lungs or hilar region, only one had led to the diagnosis of pulmonary tuberculosis. No patient with a normal chest radiograph was diagnosed to have tuberculosis within the following 2 months. The low yield (0.32%) suggests that routine chest radiography is not useful in screening for active pulmonary tuberculosis in asymptomatic HIV-infected patients even in a locality where the tuberculosis rate is high.

On 1 June 1976, the first methadone clinic was officially opened in Hong Kong, following pilot studies in the preceding years, and in response to the recommendations of Dr Robert Newman, then consultant to the Hong Kong Government. One year later, an extensive network of 21 clinics came into being, serving up to 10 000 drug users in the territory on a daily basis. Mr Peter Lee, a British colonial civil servant and then Commissioner for Narcotics, was the innovator behind this new programme. In retrospect, we argue that the low threshold methadone treatment programme is not just essential in promoting health in drug users, but has contributed to public security, and protected Hong Kong from the onslaught of HIV infection. Over the past 3 decades, the mode of operation of Hong Kong’s methadone clinics has remained the same. The clinics are operated as a walk-in methadone treatment service, for which 98% are on maintenance. Although largely a public health concept today, methadone treatment served public security objectives when it was first established. As an expensive habit, many drug users committed crime to obtain quick money to pay for their heroin. Not surprisingly, a significant proportion of the prison population in the 1960s and 1970s were drug users. Shortly after the introduction of the methadone treatment programme, crime rates fell

A survey in Hong Kong on middle-aged adults revealed a low influenza vaccination uptake rate of 13%. As a heterogeneous population comprising individuals at different levels of risk for complications, effective development of strategy for improving vaccination coverage in middle-aged adults should be prioritized.

The prevalence of human immunodeficiency virus (HIV) in men having sex with men (MSM) is generally higher than that in the average adult male population. In Hong Kong a permanent deferral mechanism is in place to minimise viral transmission during the window period. As regards donor deferral, the attitudes and behaviours of MSM in the community are crucial to ensuring blood safety.A web-based questionnaire was constructed in the Chinese language. Through online advertisement and the assistance of outreach workers, sexually active MSM were recruited to participate in the survey. The questionnaire was composed of items on: (i) demographics, (ii) history and frequency of blood donations, (iii) profile of sexual practice, and (iv) views on time-limited vs permanent deferral.Over a 6-week period in 2012, 250 MSM, three-quarters of whom were aged between 16 and 30 years old, were recruited. Almost half (47.6%) gave a history of blood donation. The majority (75.6%) were repeat donors, one-third of whom gave blood every 3-6 months. Compared to non-donors, a higher proportion of blood donors had had anal sex and multiple partners in the preceding year, while their condom usage rate was similar. Current donors were inclined to agree with time-limited deferral. With the latter's implementation, the number of donors would increase, but the compliance rate might vary widely.Blood donation is common among MSM in Hong Kong. The risk of HIV transmission depends largely on their compliance with the deferral mechanism applied, irrespectively of whether it is permanent or time-limited.

The syndemic of human immunodeficiency virus (HIV)/tuberculosis (TB) co-infection has grown as a result of the considerable sociogeographic overlaps between the two epidemics. The situation is particularly worrisome in countries with high or intermediate TB burden against the background of a variable HIV epidemic state. Early diagnosis of TB disease in an HIV-infected person is paramount but suffers from lack of sensitive and specific diagnostic tools. Enhanced symptom screening is currently advocated, and the wide application of affordable molecular diagnostics is urgently needed. Treatment of TB/HIV co-infection involves the concurrent use of standard antiretrovirals and antimycobacterials during which harmful drug interaction may occur. The pharmacokinetic interaction between rifamycin and antiretrovirals is a case in point, requiring dosage adjustment and preferential use of rifabutin, if available. Early initiation of antiretroviral therapy is indicated, preferably at 2 weeks after starting TB treatment for patients with a CD4 of50 cells/μL. Development of TB-immune reconstitution inflammatory syndrome (TB-IRIS) is however more frequent with early antiretroviral therapy. The diagnosis of TB-IRIS is another clinical challenge, and cautious use of corticosteroids is suggested to improve clinical outcome. As a preventive measure against active TB disease, the screening for latent TB infection should be widely practiced, followed by at least 6-9 months of isoniazid treatment. To date tuberculin skin test remains the only diagnostic tool in high TB burden countries. The role of alternative tests, for example, interferon-γ release assay, would need to be better defined for clinical application.

Background. Community sampling of men having sex with men (MSM) for human immunodeficiency virus (HIV) and sexually transmitted infections prevalence studies poses challenges in view of problems in logistics and the hidden nature of MSM population. Methods. MSM in Hong Kong were recruited through social venues and the Internet. All participants were invited to complete a behavioural questionnaire and submit a urine specimen for HIV, Chlamydia, and gonorrhoea testing. Results. Totally, 994 MSM were recruited. No differences between venue and online-recruited respondents were identified regarding their demographics and infection status. The prevalence of HIV, Chlamydia, and gonorrhoea was 3.6% (95% CI: 2.6–5.0%), 4.7% (95% CI: 3.6–6.2%), and 0.2% (95% CI: 0.1–0.7%), respectively. Of all HIV cases, only 8.3% were aware of the infection; reflecting newly infected MSM were probably overrepresented. Some 58.3% had had HIV test within the past year, and 11.1% had CT/NG coinfection. HIV infection was associated with group sex [aOR: 2.67 (1.03–6.92)], receiving money for anal sex [aOR: 4.63 (1.12–19.18)], and unprotected anal sex with nonregular partners [aOR: 3.047 (1.16–8.01)]. Conclusion. Difference between venue- and online-recruited MSM was observed. A combination of sampling methods is complementary for epidemiology purpose. Overall, risk behaviours practised by undiagnosed HIV-positive MSM remains a cause for concern.

Objectives: The progression of human immunodeficiency virus (HIV) disease varies considerably among infected people, being affected by factors such as virus characteristics, host response, and their interactions. Some patients with HIV may remain clinically and immunologically well for an extended period. This study aims to describe the frequency and demographic features of a group of HIV-1 positive nonprogressors in Hong Kong. Method: A retrospective study was conducted of records of a cohort of 58 HIV-1 positive patients infected for over 7 years in Hong Kong. Nonprogression is defined as the maintenance of health with no symptoms and a CD4 level of 500/μL or higher. Results: Twenty-five patients had progressed to acquired immunodeficiency syndrome (22 died); 3 had had other HIV-related symptoms; 22 were asymptomatic but had CD4 lower than 500/μL; and 8 (13.8%) were nonprogressors with no symptoms and CD4 count higher than 500/μL (median of 665/μL an average of 102.5 months after HIV detection). The nonprogressors had a relatively high CD8 level. Hemophilia with transfusion of HIV-contaminated blood products accounted for 100% of all nonprogressors, and 58% of those with clinical or immunologic progression (P = 0.041). Conclusion: These findings indicate that a proportion of HIV-infected individuals do not progress clinically or immunologically over a prolonged period. To date, all nonprogressors known to the authors are patients with hemophilia.

Using immunofluorescence and neutralization assays, we detected antibodies to human severe acute respiratory syndrome–associated coronavirus (SARS-CoV) and/or animal SARS-CoV–like virus in 17 (1.8%) of 938 adults recruited in 2001. This finding suggests that a small proportion of healthy persons in Hong Kong had been exposed to SARS-related viruses at least 2 years before the recent SARS outbreak.

Background In 2015, WHO recommended universal antiretroviral treatment for HIV irrespective of CD4 cell count. The impact of this recommendation on heterosexual HIV transmission, especially in low prevalence countries, has not been well-characterised. In Hong Kong, 38% of reported HIV cases are heterosexually acquired. We aimed to model the impacts of enhanced HIV testing and immediate treatment to provide a reference to other provinces in China. Methods We developed deterministic compartmental models (sexually active heterosexual males and females) for simulation of HIV epidemiology for 1983–2011 in Hong Kong, with data projected to 2012–20. Model parameters were derived from the literature and longitudinal clinical data from 2174 heterosexual adults who were diagnosed in 1984–2014. HIV surveillance data were retrieved from annual surveillance reports to validate projection results. The model was structured by HIV disease stages and cascade of HIV care, and in the knowledge that at least 50% of heterosexual males had acquired HIV infections non-locally. The outcome of three interventions (immediate treatment, HIV testing campaigns at 5-year intervals, and testing campaigns with immediate treatment) were examined. Ethics approval was obtained from the Joint Chinese University of Hong Kong–New Territories East Cluster Clinical Research Ethics Committee (CREC), Kowloon West Cluster Research Ethics Committee, and Kowloon East Cluster Research Ethics Committee. Data access approval was granted by Department of Health, Hong Kong Special Administrative Region Government. Findings Without interventions, the total number of HIV heterosexual prevalent cases (including undiagnosed) was projected to increase from 2804 in 2014 to 3533 by 2020 (difference 26·0% while incidence would increase from 108 new cases in 2014 to 115 in 2020 (difference 6·5%). Compared with these base rates, a testing campaign would lead to a temporary rise in new diagnoses but fewer cases overall (prevalence 3484 by 2020; difference −1·4%; incidence 108 in 2020, difference −6·5%). Immediate treatment provided smaller gains (prevalence 3528 by 2020; difference −0·1%; incidence 112 in 2020, difference −2·6%) while a testing campaign with immediate treatment (prevalence 3474 by 2020; difference −1·7%; incidence 104 in 2020, difference −9·6%) provided small additional gains to the testing campaign. Interpretation In Hong Kong, an HIV testing campaign could avert more heterosexual infections than immediate treatment alone. Our model can be applied in places where antiretroviral therapy is widely accessible, but adjustment of access to care pattern may be needed in other places with similar epidemiological profiles. Funding Council for the AIDS Trust Fund.

Sharing of contaminated injection equipment accounts for the rapid spread of the human immunodeficiency virus (HIV) among injecting drug users (IDUs). The profile of drug addiction practice among inmates of the Shek Kwu Chau Drug Rehabilitation Centre in Hong Kong was studied. Registers on all the new admissions to the Centre during a two-year period between 1990 and 1992 were reviewed. Of the 3129 drug users studied, 68.7% were aged between 21 and 40; 84.8% were IDUs and heroin was the commonest drug of addition. Nearly 70% of the IDUs had never shared injection equipment with others. There were significantly more young addicts (or = 30 years old) who had shared needles compared with the older ones (31.2% vs 26.8%, P0.05). Those with addiction time6 months were more likely to have shared needles than the new ones. Only 19% of the drug users accepted HIV testing at their first admission. Factors speculated for the low needle-sharing rates among IDUs in Hong Kong and the low HIV prevalence in the IDU population are discussed. It is of utmost importance to monitor continuously such a high-risk behaviour pattern so as to design appropriate intervention strategies to stop the transmission of HIV.

The effectiveness of a 2.5 micrograms dose of the hepatitis B vaccine (B-Hepavac II) was compared with that of 5 micrograms in 587 low-risk neonates and 777 preschool children of age 3-8 years. The vaccines were administered at months 0, 1 and 3, with postvaccination serology tested at months 4 and 12. The seroconversion rates of the 2.5 microgram recipients (newborn: 93.5%; preschool children: 97.4%) are comparable with the 5 micrograms group (newborn: 95.7%; preschool children: 98.7%). The seroconversion rates of the newborns are, however, significantly lower in the 2.5 micrograms group if positive response is taken as a titre10 IU l-1, instead of0 IU l-1. The older children, on the other hand, achieved a higher seroconversion rate and geometric mean titre (GMT) when compared with the newborns. irrespective of the dose received.

Self-deferral of men having sex with men (MSM) from blood donation is a means of protecting blood safety. There has recently been a strategy change from permanent to time-limited deferral in some countries. Awareness and attitudes of donors is crucial for effective implementation of MSM deferral or any change of the strategy.A postdonation survey was administered using a Web-based questionnaire, after explanation by trained volunteers, to evaluate donors' awareness and compliance toward the health history enquiry (HHE, the deferral questionnaire) of the Hong Kong Red Cross Blood Transfusion Service, sexual experiences, and opinions on permanent versus time-limited deferral.A total of 1373 Chinese donors (male:female 1.28:1), a majority (89.1%) of whom were repeat donors, completed the survey at eight blood donation centers. Almost all (98.7%) were aware of HHE, although only half read it in detail, the latter comprising more experienced donors. Most did not hold strong views on deferral, with more than half (59.4%) concurring with both permanent and time-limited deferral. Seventeen (3.2%) of the sexually active male donors were MSM, of whom six disagreed with permanent deferral while seven agreed with changing to time-limited deferral. A simpler question structure was preferred by 57% of the respondents for screening MSM to achieve self-deferral.Donors generally do not read through the deferral questionnaire in sufficient detail for making an informed decision. Blood safety would eventually depend on donors' compliance with the deferral mechanism, irrespective of whether it is permanent or time-limited.

Neurological and sleep disturbances were commonly reported among HIV patients on efavirenz (EFV), the pharmacokinetic pattern varies with different CYP450 2B6 G516T genotypes. This prospective study aims to detect temporal changes and differences in the profile of these adverse reactions and their relation to plasma EFV level and host genotypes. HIV patients of Chinese ethnicity on an EFV-containing HAART regimen were recruited from a specialist clinic. Blood for CYP2B6 G516T genotypes was taken. A questionnaire assessing adverse neurological problems and sleep disturbance was administered, alongside testing for plasma EFV levels at baseline, 4 weeks, 8 months and 1 year intervals after treatment. Analysis was performed using χ 2 and t-test. A total of 64 patients (31 GG, 27 GT, 6 TT genotypes, 59 male, and 5 female, mean age of 41±9.9) were recruited. At 4 weeks after EFV, 49 (76%) gave a history of any one of the neurological side effects: dizziness, headache and drunk feeling. Sleep disturbances were common: bizarre dream (45%), nightmares (35%), waking at night (73%), poor sleep quality (31%), nocturia (84%) and difficulty in falling asleep (67%). The mean plasma EFV level of GG genotype was 2.8 µg/ml and 3 µg/ml, GT genotype was 3.8 µg/ml and 3.9 µg/ml, at 4 weeks and 1 year respectively. The mean plasma EFV level of TT genotype was 11.9 µg/ml and 9.7 µg/ml at 4 weeks and 1 year respectively. There was no significant variation of drug level within each genotype over time (p>0.08), while EFV level of TT was significantly higher at all time points (p

CD4 counts rise following treatment with HAART, the pattern of which however varies between individuals and populations. Host, virus and treatment factors may play a part in shaping the trajectory. Through an HIV clinical cohort study, we aim to describe the natural course of CD4 trajectories and evaluate possible factors associated with different patterns. Between 1997 and 2008, HIV-1-infected patients receiving HAART at one major HIV specialist clinic in Hong Kong were included in a study for assessing CD4 changes. The entry criteria were: (a) patients who have been put on HAART according to standard criteria; (b) sustained viral suppression after treatment; (c) having been on HAART for at least 48 months. A total of 141 patients with 3,087 measurements were analysed, covering a total of 11,282 person-months. The median age at initiation of HAART was 37 (IQR 32-44). A majority were male (74%), Chinese (87%) and who have contracted HIV through heterosexual contacts (84%). At baseline, the median CD4 was 39 cells/µL (IQR 13-127 cells/µL) and viral load was 74,100 copies/mL (IQR 26,800-280,000 copies/mL). Over time, 80 (57%) gave a CD4 count of >500/µL during antiretroviral treatment. Clinically, almost all (96%) had presented with an AIDS-defining illness before HAART was started. Around half of the patients were on 2NRTI +1 NNRTI and half on 2NRTI +1 PI. Overall, 3 groups of patients can be differentiated by their temporal pattern of CD4 recovery. Group One (n=38; 34%) gave a median peak value of 576/µL within 4 years (median interval 40 months). Group Two comprised 96 (68%) patients whose mean CD4 count continued to rise beyond 48 months. Group Three (n=7) gave little or no response to treatment, as defined by a change of

Summary Objectives The aim of this study was to investigate the variation in hepatitis C virus (HCV) prevalence in injection drug users (IDUs) by their gathering places, using a multilevel approach. Methods IDUs recruited from their gathering places were invited to respond to a questionnaire on demographics, drug use history, injection behaviors, and methadone treatment. Dried blood spots were collected for HCV antibody testing by ELISA. Factors associated with the anti-HCV test result were explored by linear logistic regression, followed by the evaluation of heterogeneity between gathering places by multilevel analysis. Results A total of 622 respondents from 19 gathering places in Hong Kong, recruited between August and September 2011, were evaluated. Anti-HCV seroprevalence was 81.7% (95% confidence interval 78.6–84.7%), ranging from 67% to 100% by gathering place. HCV infection was associated with current practice of injection, needle-sharing, and midazolam injection. On multilevel analysis, there was a modest but significant variation in HCV antibody prevalence by gathering place, adjusted by midazolam injection (adjusted odds ratio (AOR) 3.91) and current injection (AOR 2.88) or injection over a long duration (AOR 3.17). Conclusions There was heterogeneity in HCV antibody prevalence in IDUs by gathering place, while the influence of injection behaviors varied, suggesting interactivity between factors at the individual and group levels.

Background Advances in communication technology may affect networking pattern, thereby influencing the dynamics of sex partnership. The aim of the study is to explore the impacts of partner sourcing through internet and related channels on exposure risk to sexually transmitted infections (STI) including HIV. Methods Using venue-based sampling, a cross-sectional questionnaire survey was conducted at saunas frequented by men having sex with men (MSM) in Hong Kong. Comparison was made between MSM sourcing partners through physical venues alone versus concomitant users of physical and virtual channels, the latter referring to internet and smart-phone applications, using bivariate logistic regression. Results Over a 7-week study period, 299 MSM were recruited from 9 saunas. Three main types of sex partners were distinguished: steady (46.8%), regular (26.4%) and casual (96.0%) partners. Users of sauna (n = 78) were compared with concomitant users of saunas and virtual channels (n = 179) for partner sourcing. Sauna-visiting virtual channel users were younger and inclined to use selected physical venues for sourcing partners. Smart-phone users (n = 90) were not different from other internet-users in terms of age, education level and single/mixed self-identified body appearance. Classifying respondents into high risk and low risk MSM by their frequency of condom use, concomitant use of both sauna and virtual channels accounted for a higher proportion in the high risk category (71.6% vs. 58.2%, OR = 1.81, p

The distribution of HCV genotypes among injection drug users in Hong Kong was assessed in context of methadone treatment availability. Three time periods were defined by the year of initiating injection—on or before 1980, 1981–1994, and 1995–2006—with methadone becoming widely available since the second period. Of the 273 HCV RNA-positive cases, the most prevalent subtype was HCV 6a (52.4%), followed by HCV 1b (38.5%). The new variants of HCV subtypes 6e and 6h were detected. Both subtypes 1b and 6a were prevalent among older injectors, while subtype 3a was more common in young injectors and those initiating injection recently during the third time period. Age (P

OBJECTIVE To evaluate the advantages and drawbacks of six commercially available techniques in the measurement of microalbuminuria in diabetic patients. RESEARCH DESIGN AND METHODS Timed overnight urine samples from 75 patients in our diabetic clinic were tested with 2 qualitative tests (Micral-Test and Microbumintest) and assayed with 4 quantitative tests, which used different methodologies: double-antibody RIA, RID, IT, and NEPH. All tests were commercially available. The double-antibody RIA was taken as the golden standard. All urine samples were either negative or trace by Albustix (Ames, Elkhart, IN). Interobserver variation for the 2 qualitative tests was assessed by asking 12 experienced nurses to read the color changes on the dipsticks and the tablets simultaneously, using test solutions with albumin concentrations of 16, 32, and 64 mg/L. RESULTS The 75 urine samples contained 0–154.2 mg/L of albumin. Correlation coefficients of RID, NEPH, and IT with RIA were 0.970, 0.975, and 0.974, respectively. Intra-assay and interassay CVs ranged from 1.36–11.5%. Microbumintest had a higher sensitivity (100 vs. 75%), but lower specificity (82.5 vs. 87.3%) than Micral-Test. Considerable interobserver variation existed in the matching of colors for both tests. Discrepancies were especially significant with Microbumintest, with 8 of 12 nurses misreading the 32 mg/L level. CONCLUSIONS Correlations of the 3 quantitative methods with RIA were all >0.970. Choice of test may depend more on considerations such as time, space, number of specimens to be handled, and availability of instruments. Both qualitative tests showed a relatively low specificity. Positive tests must be confirmed with quantitative assays before microalbuminuria is diagnosed. Microbumintest had a higher sensitivity, but its unacceptably high interobserver variation and lower specificity were serious drawbacks.

Using Geographic Information System (GIS), the spatial distribution of methadone clinic clients and their utilization of a treatment service in Hong Kong was analysed. A majority (93.7%) of the 63 methadone users recruited were residing in the same district, of which 84.1% spent not more than 15 minutes for traveling. Walking (55.6%) was the commonest transport mode followed by cycling (30.2%). There was no distance decay effect on traveling time, but an association between distance and transport selection could be demonstrated. The residence locations displayed a compact distribution, merging with the general population without any evidence of clustering. Though the distribution of methadone users could have been shaped by the location of clinic, it can also be concluded that methadone clinics at convenient locations are needed if maintenance is a key determinant of service effectiveness.

Background The incidence and prevalence of sexually transmitted infection (STI) in China has been on the rise in the past decade. Delineation of epidemiologic pattern is often hampered by its uneven distribution. Spatial distribution is often a neglected aspect of STI research, the description of which may enhance epidemiologic surveillance and inform service development. Methods Over a one month-period, all first time attendees of 6 public STI clinics in Hong Kong were interviewed before clinical consultation using a standard questionnaire to assess their demographic, clinical and behavioural characteristics. A GIS (geographic information system)-based approach was adopted with mapping performed. The cases attending the clinics in different locations were profiled. A comparison was made between neighbourhood cases (patients living near a clinic) and distant cases (those farther off), by calculating the odds ratio for demographic, behavioural and geographic characteristics. Results Of the 1142 STI patients evaluated, the residence locations of 1029 (90.1%) could be geocoded, of which 95.6% were ethnic Chinese and 63.4% male. Geographically only about a quarter lived in the same district as the clinic. STI patients aged 55 or above were more likely to be living in the vicinity of the clinic, located in the same or adjacent tertiary planning unit (a small geographic unit below district level). A majority of patients came from locations a few kilometers from the clinic, the distance of which varies between clinics. Overall, more syphilis cases were reported in patients residing in the same or adjacent tertiary planning unit, while distant cases tended to give a higher risk of inconsistent condom use. There were otherwise no significant clinical and epidemiologic differences between neighbourhood and distant STI cases. Conclusions There was no specific relationship between STI and the residence location of patients as regards their clinical and epidemiologic characteristics in the territory of Hong Kong. Older STI patients were however more inclined to attend the nearby STI clinics. Most patients have travelled a variable distance to access the STI service. The relationship between STI clinic cases and distance could be a complex issue intertwined between psychosocial characteristics and STI service coverage.

Background Fever is an undifferentiated clinical feature that may enhance the sensitivity of syndromic surveillance systems. By studying the spatiotemporal associations of febrile patients, it may allow early detection of case clustering that indicates imminent threat of infectious disease outbreaks in the community. Methods We captured consecutive emergency department visits that led to hospitalization in a district hospital in Hong Kong during the period of 12 Sep 2005 to 14 Oct 2005. We recorded demographic data, provisional diagnoses, temperature on presentation and residential location for each patient-episode, and geocoded the residential addresses. We applied Geographical Information System technology to study the geographical distribution these cases, and their associations within a 50-m buffer zone spatially. A case cluster was defined by three or more spatially associated febrile patients within each three consecutive days. Results One thousand and sixty six patient-episodes were eligible for analysis; 42% of them had fever (>37°C; oral temperature) on presentation. Two hundred and four patient-episodes (19.1%) came from residential care homes for elderly (RCHE). We detected a total of 40 case clusters during the study period. Clustered cases were of older age; 57 (33.3%) were residents of RCHE. We found a median of 3 patients (range: 3 - 8) and time span of 3 days (range: 2 - 8 days) in each cluster. Twenty five clusters had 2 or more patients living in the same building block; 18 of them were from RCHE. Conclusions It is technically feasible to perform surveillance on febrile patients and studying their spatiotemporal associations. The information is potentially useful for early detection of impending infectious disease threats.

With considerable capacity for genetic diversification, new HIV-1 genotypes have been reported over the years. Three HIV-1 isolates previously genotyped as B using gag and env sequences were completely sequenced and reanalyzed. Several amino acid mutations were found in vif, rev, and nef genes but not in gag or env sequences. These alterations have not previously been reported in Hong Kong. The investigation of phylogenetic relatedness revealed that a region of the vif of the studied Hong Kong isolates subtype B cluster contains several subtype D signature amino acid residues. Several unique mutations on vif in these three isolates were also identified.

Summary Objective To investigate the molecular epidemiology of recently diagnosed HIV-1 infection in Macao for better understanding the epidemiology in this Chinese city, in context of its relationship with other countries in Asia and the rest of the world. Methods Serum samples of HIV positive cases reported between 2005 and 2007 were collected from the Macao Public Health Laboratory. HIV genotype was determined by phylogenetic analysis of sequences from gag , RT, and env regions. Results A total of 30 HIV positive samples were genotyped. The HIV-1 viruses circulating in Macao were characterized by their relatively high genetic diversity. CRF01_AE was predominant (56%), followed by subtype B (13%), CRF12_BF (10%), G/CRF12_BF, A1/CRF10_AD and CRF07_BC, of which CRF12_BF and G/CRF12_BF were first reported in Southeast Asia. Phylogenetic analysis showed that there was no clear clustering of CRF01_AE strains but a distinct CRF12_BF cluster associated with injection drug use could be delineated. Conclusion The results suggested that there were multiple introductions of HIV strains in Macao that have been circulating for an extended period of time, superimposed by an outbreak in injection drug users.

Objective: To explore the clustering of HIV infected men having sex with men (MSM) using social network approach in conjunction with the phylogenetic relationship of the virus strains. Design: An exploratory study incorporating social network and phylogenetic analysis. Methods: Recently diagnosed HIV-infected MSM attending one major HIV specialist clinic in Hong Kong were recruited in the study involving the administration of a selfadministered questionnaire on behaviours and partnership patterns using a Likert Scale, the results of which were assessed using social network analysis and in context of the phylogenetic analysis from sequencing the HIV-1 pol gene, as part of the clinical investigation for genotypic resistance. Clusters were defined using social and molecular methods. Results: An ‘Internet-centred’ cluster and ‘Sauna-centred’ cluster could be delineated using correspondence analysis and network diagrams. The main distinguishing features of MSM in the ‘Internet-centred’ social cluster were: younger age, higher education level, and multiple partner types. Three genetic clusters could be identified in the phylogenetic tree, two of which associated with Internet use and one with sauna for sex partnership. There were partial overlaps between social and genetic clusters. Characteristically, the virus strains in sauna users were more disperse compared with the closely knit configuration of those using Internet. Conclusion: The principle of the duality of place and person can be strategically applied in epidemiologic investigation. The characterization of MSM cluster using anonymized network data provides a potentially powerful tool for informing public health intervention.

A self-administered network-based questionnaire survey was conducted on 91 HIV-positive Chinese men having sex with men (MSM). Affiliation matrices were created to assess their networking pattern. The individuals’ preferential use of venues for sex partnership before HIV infection has changed over three time periods of 1997–2000, 2001–2003 and 2004–2006. Over time, there was a parallel increase in network density (density scores from 0.26, through 0.36, to 0.53) and degree centrality (from a median score of 9, through 12, to 16), suggesting that connectivity of MSM was becoming higher through sexual networks. The overall practice of unprotected sex has, however, remained the same. The study demonstrated how the application of social network analysis could enrich the epidemiologic description of HIV infection in the population. Keywords: HIV, Men having sex with men, MSM, Social network analysis

In Hong Kong, heterosexual transmission has long been the major mode of HIV spread. Reported HIV infection has, however, gradually risen in men who have sex with men (MSM), overtaking heterosexual contacts in men as the main route of HIV transmission after the year 2004. A survey in 2006/ 2007 confirmed that 4% of tested MSM were positive for HIV antibody. Engaging in unsafe sex is often considered the reason behind the rising HIV prevalence in MSM. To understand the dynamics of HIV transmission in Hong Kong, we conducted a study to explore the partnership pattern of MSM before their HIV diagnosis. In the 8-week period between November 2006 and January 2007, 121 HIV-positive Chinese MSM attending a specialist clinic were successfully interviewed. Overall, 53 (46.1%) were infected during or before 2000, whereas 62 (53.9%) were infected afterwards. Using the same cut-off year, the age of infection was higher (33.7 v. 30.1, t= –2.02, P< 0.05) in those infected after v. during or before 2000. There was in general a 1–2 year lag period between infection and diagnosis, a phenomenon that has not changed over years. A Likert scale was used to assess mixing pattern and sexual activities. A majority indicated that their sex partners were people of similar age (72%) or not more than 10 years older or younger. A higher proportion of older individuals above the age of 38 had sex partners more than 10 years younger (27.9% v. 10.3% odds ratio [OR] 3.35; 95% confidence interval [CI] 1.22–9.23), but there has been no change after 2000. Over 90% expressed that they largely (Likert scale 4–6) had sex with local Chinese. There was no demonstrable difference in the pattern of mixing in terms of age and ethnicity, between those infected during or before and after 2000. The type of sexual activities was assessed. There was no statistically significant difference during or before and after 2000 in the proportion of respondents who practised anal sex (54.7% v. 62.9%), oral sex (79.2% v. 83.9%) and/or masturbation (84.9% v. 85.5%) predominantly (Likert scale 4–6). The use of a condom for anal sex has remained the same (64.2% v. 68.3%), whereas that for oral sex has, however, declined (21.2% v. 9.8%, OR= 2.2, P < 0.05). Similarly, the proportion of those admitting the use of soft drugs has increased (39.6% v. 53.2%, OR= 1.73, P < 0.05) after 2000. Table 1 shows the distribution of locations that MSM in our study population used for sourcing partners and for sex. The internet has become one of the most important modes of becoming acquainted with sex partners after 2000 (45.2% v. 7.5% OR= 10.09, P< 0.05). The frequency of anal sex was higher in internet users (71.4% v. 50.8%, OR= 2.41, P < 0.05), but there was no difference in the use of condom for both anal and oral sex. Interestingly, the respondents’ home has now stood as one of the most popular locations for sex for those infected after 2000 (26.4% v. 45.2%, OR= 2.29, P < 0.05). In this study we observed major changes in the networking pattern of Chinese MSM in Hong Kong, a phenomenon that might have predated the rising HIV prevalence. Apparently, the Table 1. Comparison of locations for sexual partnership in men who have sex with men between two time periods – those infected with HIV in 2000 or before and others in 2001 or after *P < 0.05

BACKGROUND: While human cases of highly pathogenic avian influenza A (H5N1) virus infection continue to increase globally, available clinical data on H5N1 cases are limited. We conducted a retrospective study of 26 confirmed human H5N1 cases identified through surveillance in China from October 2005 through April 2008. METHODOLOGY/PRINCIPAL FINDINGS: Data were collected from hospital medical records of H5N1 cases and analyzed. The median age was 29 years (range 6-62) and 58% were female. Many H5N1 cases reported fever (92%) and cough (58%) at illness onset, and had lower respiratory findings of tachypnea and dyspnea at admission. All cases progressed rapidly to bilateral pneumonia. Clinical complications included acute respiratory distress syndrome (ARDS, 81%), cardiac failure (50%), elevated aminotransaminases (43%), and renal dysfunction (17%). Fatal cases had a lower median nadir platelet count (64.5 x 10(9) cells/L vs 93.0 x 10(9) cells/L, p = 0.02), higher median peak lactic dehydrogenase (LDH) level (1982.5 U/L vs 1230.0 U/L, p = 0.001), higher percentage of ARDS (94% [n = 16] vs 56% [n = 5], p = 0.034) and more frequent cardiac failure (71% [n = 12] vs 11% [n = 1], p = 0.011) than nonfatal cases. A higher proportion of patients who received antiviral drugs survived compared to untreated (67% [8/12] vs 7% [1/14], p = 0.003). CONCLUSIONS/SIGNIFICANCE: The clinical course of Chinese H5N1 cases is characterized by fever and cough initially, with rapid progression to lower respiratory disease. Decreased platelet count, elevated LDH level, ARDS and cardiac failure were associated with fatal outcomes. Clinical management of H5N1 cases should be standardized in China to include early antiviral treatment for suspected H5N1 cases.

SUMMARY Anti-neutrophil cytoplasmic antibodies (ANCA) are important diagnostic markers in vasculitic disorders. In a study of 164 patients with various clinical syndromes associated with vasculitis, 60 were found to have the antibody, as detected by indirect immunofluorescence; 23 had the so-called perinuclear antibody pattern, and of these, 15 had antibodies to neutrophil myeloperoxidase in an ELISA. These patients had multi-system involvement, and 14 of the 15 had histological evidence of small-vessel arteritis in the kidneys. In preliminary experiments, the isolated IgG from one patient was shown to inhibit luminol-dependent chemiluminescence of fluid phase myeloperoxidase.

Dengue is a mosquito-borne infection the incidence of which varies with the environment and climate. Knowingly, the reported incidence of dengue is an insensitive indicator of infection risk in a locality. The Ovitrap Index has been in use in many countries. This index is a measurement of mosquito eggs in specified geographic locations which, in turn, reflects the distribution of Aedine mosquitoes, the vector for dengue. An alert system, founded on the Geographic Information System (GIS) technology, was created from a synthesis of geospatial data on ovitrap indices in Hong Kong. The inter-relationship between ovitrap indices and temperature was studied. This inference forms the rationale for the generation of weighted overlays to define risk levels. The weighting can be adjusted to set the sensitivity of the alert system. The system is operational at two levels: (1) for the general public to assist in the evaluation of dengue risk in the community, and (2) for professionals and academia in undertaking technical analysis. The alert system offers one objective means to defining the risk of dengue in a society, which would not be affected by the incidence of the infection itself.

Epstein-Barr virus (EBV)-associated smooth muscle tumor (SMT) is a recognized but uncommon disease that is found to occur in patients with immunocompromised conditions such as acquired immunodeficiency syndrome (AIDS). These tumors may be multifocal and located at unusual sites, such as the brain and liver. This report describes the case of 2 AIDS patients with EBV-associated SMT and highlights the features and outcome of this rare but potentially important tumor in human immunodeficiency virus management.

Background In Hong Kong, methadone treatment is widely accessible. Injecting drug users (IDU) have a relatively low risk behavioural profile and low HIV prevalence (0.3%). The corresponding Hepatitis C (HCV) level, however, is unclear. Objectives To determine the HCV prevalence in IDU in Hong Kong and to identify any associated factors. Study Design A community-based HCV prevalence study of IDU was conducted in methadone clinics. Demographics and drug use pattern were collected through a questionnaire survey and blood samples were obtained for HCV serological tests. Results Data of 567 IDU were analyzed. Most were male (84%) and ethnic Chinese (98%). The median age was 49 years and median injection duration 17 years. Two-thirds (62%) admitted ever sharing injecting equipments. Most (76%) reported having injection drug use in the preceding 3 months, and 44% abused midazolam/triazolam in addition to heroin. Prevalence of HCV antibodies was 85% (95% confidence interval 82.5–88.3%). Injection duration, recent injection, ever sharing injecting equipments and concomitant use of other drugs were independent factors associated with HCV infection. Conclusions HCV prevalence is high in IDU despite a low HIV prevalence and widely available substitution treatment, which has probably slowed but not prevented the HCV epidemic in IDU in Hong Kong.

A self-administered questionnaire survey was conducted in a specialist HIV clinical service in Hong Kong. A total of 76 male Chinese patients who had been on highly active antiretroviral therapy for over one year were enrolled. All except one had undetectable viral load at the time of the assessment. Though a majority (76%) scored 100% in self-reporting adherence rating, one-third of these had in fact missed at least one dose in the preceding four-week period. Men having sex with men had a lower tendency of missing dose than heterosexuals (13.6% versus 42%, P = 0.019). There was no association between missing doses and clinical staging or the regimens. The study revealed that missing doses may occur despite report of almost complete adherence, which, in the long run, could be a cause for concern.