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Summary Background Healthcare workers (HCWs) are at risk of influenza infection with associated nosocomial transmission. Sustained adherence to seasonal influenza vaccination uptake each year is important in epidemic control. Aim To assess the adherence of nurses to seasonal influenza vaccination over 5 years and its associated factors. Methods A cross-sectional study was conducted among nurses after the winter influenza season in Hong Kong in March 2019. Based on influenza vaccine uptake rates in the 2014/15–2018/19 seasons, respondents were stratified into three groups: ‘full adherence’ (vaccine uptake in five seasons), ‘partial adherence’ (vaccine uptake in one to four seasons) and ‘non-adherence’ (no vaccine uptake). Stepwise multi-variable logistic regression was performed to determine the associations between adherence to annual influenza vaccination, respondents’ characteristics and considerations for vaccination. Findings Of 1306 nurses recruited, the majority were female (88%) with a median age of 36 years (interquartile range 30–46 years). The influenza vaccination uptake rate increased from 36% in the 2014/15 season to 47% in the 2018/19 season. After stratification, 39%, 40% and 21% of respondents were non-adherers, partial adherers and full adherers, respectively. Full adherence was significantly associated with female gender [adjusted odds ratio (aOR) 0.60], age ≥40 years (aOR 2.92), long-term care facility nurse (aOR 0.56), uptake during studentship (aOR 3.83), local prevalence of seasonal influenza (aOR 0.51) and expert opinion (aOR 4.04). Conclusions A limited proportion of nurses were fully adherent to seasonal influenza vaccination. Monitoring adherence, improving access to vaccines, and interventions targeting less-adherent HCWs are crucial.

Failure of pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate and emtricitabine may occur despite perfect adherence, although this is uncommon. Failure results in breakthrough HIV infection. Delayed seroconversion associated with antiretroviral use may complicate the picture, causing uncertainties in interpreting adherence patterns for establishing the true cause of PrEP failure.

Summary This study explored how cultural values affected Health Belief Model (HBM) components and the influenza vaccine uptake among nurses across three Asian populations using a survey conducted in 2017 (N = 3971). The vaccination coverages were 33.5% (Brunei), 35.6% (Hong Kong) and 69.5% (Singapore). Three HBM components (perceived susceptibility, perceived benefits and cues to action) were positively associated with vaccination. A direct negative link and an indirect positive link via HBM were observed between collectivism and vaccination, whereas a negative indirect link via HBM between power distance and vaccination was observed. Cultural values, notably collectivism, advanced HBM to study nurses' vaccination.

Aim The purpose of this perspective is to review the options countries have to exit the draconian “lockdowns” in a carefully staged manner. Methods Experts from different countries experiencing Corona Virus Infectious Disease 2019 (COVID-19) reviewed evidence and country-specific approaches and the results of their interventions. Results Three factors are essential: 1. Reintroduction from countries with ongoing community transmission; 2. The need for extensive testing capacity and widespread community testing, and 3. An adequate supply of personal protective equipment, PPE, to protect health care workers. Discussed at length are lifting physical distancing, how to open manufacturing and construction, logistics, and the opening of higher educational institutions and schools. The use of electronic surveillance is considered. Conclusion Each country should decide on the best path forward. However, we can learn from each other, and the approaches are, in reality, very similar.

Summary Seasonal influenza vaccine uptake rate of healthcare workers (HCWs) varies widely from 90% worldwide. Perception of vaccine efficacy and side-effects are conventional factors affecting the uptake rates. These factors may operate on a personal and social level, impacting the attitudes and behaviours of HCWs. Vaccination rates were also under the influence of the occurrence of other non-seasonal influenza pandemics such as avian influenza. Different strategies have been implemented to improve vaccine uptake, with important ones including the enforcement of the local authority's recommendations, promulgation of practice guidelines, and mandatory vaccination polices. Practised in some regions in North America, mandatory policies have led to higher vaccination rate, but are not problem-free. The effects of conventional educational programmes and campaigns are in general of modest impact only. Availability of convenient vaccination facilities, such as mobile vaccination cart, and role models of senior HCWs receiving vaccination are among some strategies which have been observed to improve vaccination uptake rate. A multi-faceted approach is thus necessary to persuade HCWs to participate in a vaccination programme, especially in areas with low uptake rate.

Background A healthy healthcare system requires healthy healthcare workers. Protecting healthcare workers including nurses against COVID-19 is crucial, and vaccination could be a viable future option. However, vaccine hesitancy remains a global challenge. Nurses, as a trustworthy and creditable source of vaccine-related information, may build public confidence in vaccination. Hence, research on vaccine hesitancy among nurses is warranted. Objectives This study estimated nurses’ influenza vaccination behaviors and intention to receive COVID-19 vaccine when available, and examined their corresponding 5C psychological antecedents (confidence, complacency, constraints, calculation, and collective responsibility). To investigate the impact of COVID-19-related work demands, the mediation effects of work stress on the association between work demands and COVID-19 vaccination intention were also examined. Design Cross-sectional online survey Settings Nurses were invited to participate via the promotion of a professional nursing organization and by personal referrals during the COVID-19 outbreak in Hong Kong between mid-March and late April 2020. Participants 1,205 eligible nurses (mean age = 40.79, SD = 10.47; 90% being female) were included in the analyses. Methods Demographics, influenza vaccination, intention to have COVID-19 vaccine, the 5C vaccine hesitancy components, work stress and COVID-19-related work demands (insufficient supply of personal protective equipment, involvement in isolation rooms, and unfavorable attitudes towards workplace infection control policies) were reported in the survey. Results The influenza vaccine uptake rate and the proportion intending to take COVID-19 vaccine were 49% and 63%, respectively. Influenza vaccination was associated with working in public hospitals and all 5C constructs (more confidence, more collective responsibility and less complacency, constraints, and calculation), whereas stronger COVID-19 vaccination intention was associated with younger age, more confidence, less complacency and more collective responsibility. COVID-19-related demands were associated with greater work stress, and hence stronger COVID-19 vaccination intention. Conclusion The potential uptake rate of COVID-19 vaccine among nurses was suboptimal to achieve herd immunity. The 5C constructs were useful in predicting influenza vaccination and, to a lesser extent, the intention to take COVID-19 vaccine. The uncertain attributes such as effectiveness, side effects, and effective duration of the COVID-19 vaccine may contribute to this discrepancy. With less work stress among nurses in the post-pandemic period, the intention to take COVID-19 vaccine will likely drop. The 5C constructs should be infused in vaccination campaigns. While a COVID-19 vaccine could be ready soon, the nursing profession may not be ready to accept it. More research work is needed to boost the uptake rate. Tweetable abstract Less than two-third of nurses intended to take COVID-19 vaccine when available. While a COVID-19 vaccine could be ready soon, nursing profession is not ready to accept it.

Background Clofazimine (CFZ), a riminophenazine, is now commonly used in the treatment of multidrug-resistant tuberculosis. However, its use may be potentially associated with cardiac dysfunction in some individuals. In this study, the zebrafish heart, by merit of its developmental and genetic characteristics being in homology with that of human, was chosen as an animal model for evaluation of such dysfunction. Methods Morphological and physiological parameters were used to assess cardiac dysfunction. Transcriptome analysis was performed, followed by validation with real-time quantitative PCR, for delineation of the relevant genomics. Results Exposure of 2 dpf zebrafish to 4 mg/L CFZ for 2 days, adversely affected cardiac functions including significant decreases in HR, SV, CO, and FS, with observable pathophysiological developments of pericardial effusion and blood accumulation in the heart, in comparison with the control group. In addition, genes which respond to xenobiotic stimulus, related to oxygen transport, glutathione metabolism and extracellular matrix -receptor interactions, were significantly enriched among the differentially up-regulated genes. Antioxidant response element motif was enriched in the 5000 base pair upstream regions of the differentially expressed genes. Co-administration of N-acetylcysteine was shown to protect zebrafish against the development of CFZ-induced cardiac dysfunction. Conclusions This study suggests an important role of oxidative stress as a major pathogenetic mechanism of riminophenazine-induced cardiac dysfunction.

Background Adherence to monitoring and prescription of pre-exposure prophylaxis (PrEP) is important in effectively preventing HIV infection. We aimed to establish the retention rate of men who have sex with men (MSM) who enrolled in a PrEP implementation study in Hong Kong, China. Methods Our study was a survival analysis of a crossover study. A research clinic was set up in the teaching hospital of the university to recruit participants through community-based organisations or by self-referral. Participants were randomly assigned by block randomisation with a block size of four to two groups during the study period (32 weeks split into two 16-week phases); in the first group, participants were asked to take PrEP every day for the first 16 weeks then on demand for the remaining 16 weeks, and in the second group, participants took PrEP on demand for the first 16 weeks then ever day for the remaining 16 weeks. Eligible participants were adult HIV-negative MSM with a history of high HIV-risk behaviours or sexually transmitted infections in the preceding 6 months and an inclination to practice condomless sex in the coming 6 months. The exclusion criteria were hepatitis B virus infection, creatinine clearance lower than 60 mL per min, with or without mental illnesses. We assessed behavioural factors associated with retention by bivariate analysis. We used cox regression to characterise participants who had dropped out of the study. The study was approved by the Joint Chinese University of Hong Kong-New Territories East Cluster Clinical Research Ethics Committee (CREC 2016.719). The trial is registered with the Centre for Clinical Research and Biostatistics, The Chinese University of Hong Kong, Hong Kong, China (trial number CUHK_CCRB00606). Findings Between Aug 25, 2018, and Mar 23, 2019, we recruited 120 MSM. Of the 120 MSM recruited, one ( Interpretation The retention was high in a trial setting. Defaulters who had receptive anal sex or HIV-positive sex partners might have continued HIV risk, therefore other prevention measures should be made available if PrEP was not sought elsewhere. The role of intimate or sex partners in retention in PrEP programmes should be explored. Funding AIDS Trust Fund (MSS 292 R).

Summary Objective To assess the potential risk of dengue transmission in a non-endemic city using a spatial epidemiological approach. Methods Past dengue exposure of the general population was examined by dengue virus (DENV) IgG testing of archived samples from voluntary blood donors. Vector intensities were determined by local ovitrap index (OI). Analyses were made in the context of population statistics at both the district and sub-district level. Results The overall prevalence of DENV IgG was low at 2.25%. Positive donors were more likely to be older, non-Chinese, and female. Neither the OI nor the location of residence was associated with DENV serology. The sub-district level OI was clustered, but no correlation could be confirmed with the location of residence of positive blood donors. Conclusions The cumulative exposure of Hong Kong residents to dengue has so far been low. Coupled with the lack of a spatial relationship between exposed cases and vector intensities, a high risk of local transmission of DENV is not supported. The apparently higher exposure likelihood of females could be explained by past infection in workers from dengue endemic countries, while frequent travel could have exposed older adults to DENV. Continued surveillance, risk assessment, and intensive vector control remain essential to prevent the transformation of a non-endemic to an endemic city.

Background Despite being recommended by many medical organizations, the uptake rates of seasonal influenza vaccination among healthcare workers, including nurses, are still unsatisfactory. Considering the impact of cultural values on organizational behaviors, vaccination among nurses may also be influenced by cultural values via their impacts on socially oriented motivation and the acceptance of social influence. Objectives This study examined whether and in what way two individual-level cultural dimensions, collectivism and power distance, would influence vaccination via social benefits (i.e., self-and-clan protection and community protection) and social influence (i.e., authority advice, and family-and-peer advice), respectively, among nurses. Design A cross-sectional online survey. Setting An invitation to participate in the survey was sent to nurses using the contact list of a professional nursing organization in Hong Kong and by personal referrals. Participants A total of 1386 nurses (mean age = 37.82, SD = 10.36; 89% women) completed the survey. Methods The survey included instruments on cultural values, perceived social benefits, and social influence, and questions regarding 2-year vaccination records. The mediation model was tested using structural equation modeling with bootstrapped samples. Subgroup analyses were conducted to examine whether the mediation paths were different across different levels of demographic factors. Results The structural paths in the mediation model were different between nurses that had been vaccinated in the past and those who had not. In the adoption model (i.e., for nurses non-vaccinated in the past), the positive effects of collectivism on vaccination were mediated by self-and-clan protection and authority advice, whereas the negative effect of collectivism on vaccination was mediated by community protection. In addition, the positive effect of power distance on vaccination was mediated by authority advice. In the maintenance model (i.e., for nurses vaccinated in the past), except for the positive effect of collectivism on vaccination via authority advice, the other indirect effects were not significant. The direct effect of collectivism on vaccination was negative, whereas the direct effect of power distance on vaccination was positive. Conclusions Collectivism and power distance may guide how nurses attend to and process social information and subsequently influence their vaccination adoption behaviors. More research is needed to examine how cultural dimensions may influence vaccination maintenance and the applicability of the current findings to other cultures.

Background Understanding the driving forces of HIV infection is crucial for developing intervention strategies. We aimed to infer these forces from genetic linkages between past and newly diagnosed cases by a molecular approach. Methods We recruited newly diagnosed HIV patients from all three HIV specialist clinics in Hong Kong, China, between 2016 and 2018 to collect their HIV sequences with corresponding behavioural and clinical data. We retrieved archived HIV sequences from 1994 to 2012 separately. We pooled and analysed sequences by constructing a network with 1·5% TN93 distance threshold and measured node degree centrality. We did univariate analyses to identify factors associated with genetic links with archived sequences among newly diagnosed patients, and used a generalised linear model to differentiate archived sequences having links with new cases adjusting for diagnosis year. Findings 2778 partial pol sequences were amalgamated for network construction, of which 426 were newly diagnosed. The network contained 1908 (69%) nodes and 23 305 edges. Some 703 (3%) edges linked 192 archived samples with 135 new cases. Of 239 newly diagnosed patients with genetic connections, those linked with past infections were more likely to be subtype B (odds ratio 3·31; p Interpretation HIV transmission chains linking new with past infections in Hong Kong were driven by younger MSM. Chemsex, emergence in recent years, only clustered in and contributed to some new infections. Formation of transmission linkages over time signified the importance of targeting new and established infections in developing prevention strategies. Funding Research Grants Council of Hong Kong (14103315) and AIDS Trust Fund (MSS 229 R and 243 R).

Elderly people are at higher risk of influenza diseases. The morbidity benefit of vaccination is often offset by its low and variable coverage in elderly people in the community. To assess household and individual factors associated with influenza vaccination uptake in the community-dwelling elderly of age ≥ 65, data from a cross-sectional Thematic Household Survey conducted in 2011/12 in Hong Kong were analysed, using vaccination in the past 12 months as the outcome variable. Households comprising an elderly person living with non-elderly member(s) of age ≤ 64 were also evaluated. Data fields included socio-demographics, household structures, health status, eligibility to financial subsidy, and subscription to health insurance. The influenza vaccination rate was 27% in 4204 elderly persons from 3224 households. Being male, being economically active, attaining primary education, having smoking behaviours were negatively associated with vaccination, while chronic illness and age ≥ 70 were positively associated factors. Elderly people living alone gave a variable rate of vaccination ranging from 16.4% in males of age 65–69 to 36.3% in females ≥ 70. Household size per se was not associated with vaccination, but a positive correlation could be seen if the household was composed of vaccinated non-elderly member(s). Influenza vaccination uptake in the community-dwelling elderly is dependent on both individual and household characteristics, the latter including the influence of vaccinated non-elderly member(s). The low vaccination coverage of “younger” (age 65–69) elderly men living alone is particularly worrisome. Interventions focusing on vulnerable elderly people and their social networks would be desirable., Highlights • Influenza vaccination coverage was

Background In Hong Kong, pre-exposure prophylaxis (PrEP) was first launched as a pilot study for men who have sex with men (MSM) at high risk of HIV infection. However, the community's acceptance of such programme might affect policy making in its implementation as a service. Therefore, we aimed to examine the feasibility of an incentivised mode of PrEP delivery in the MSM community. Methods We did a implementation study of daily co-formulated tenofovir disoproxil fumarate 300 mg plus emtricitabine 200 mg (TDF/FTC). We prescribed oral tablets of TDF/FTC to PrEP-naive, HIV-negative, high-risk MSM for 30 weeks through a pilot clinic in Hong Kong. We assessed MSM that self-referred or were referred by collaborating community organisations or HIV services using a survey about their eligibility and, if applicable, reasons for not joining the study. The key inclusion criteria were recent history of condomless anal sex and HIV negative on testing, whereas HBsAg-positive patients and those with impaired renal functions were excluded. The primary measures were acceptance rate and associated socio-behavioural factors. Consenting MSM were required to pay a fixed price at each visit but the follow-up interval was increased over time, such that the unit cost of TDF/FTC became lower for participants who remained on the programme. The actual cost of TDF/FTC was equivalent to HK$25 (US$3·20) per tablet or 13% of the market price upon completion. The study was approved by the Joint Chinese University of Hong Kong–New Territories East Cluster Clinical Research Ethics Committee. This study is registered with the Centre for Clinical Research and Biostatistics Clinical Trials Registry, number CUHK_CCRB00533, and the Chinese Clinical Trial Registry, number ChiCTR-OPC-16009603. Findings Between Sep 21, 2017, and May 23, 2018, 292 MSM were assessed. Among 247 MSM who showed interest in the study, 196 (79%) had engaged in high-risk behaviours in the preceding 6 months. Among 229 high risk MSM, 196 (86%) indicated willingness to join the study, of which 71 ultimately enrolled. 49 (98%) of 50 MSM who used drugs during sex were interested in joining the programme (p=0·004). There were no significant associations between risky behaviours, such as the practice of condomless sex, and PrEP acceptance. The most common reason for not being interested in the study was the drug cost (24 [53%] of 45), concern about side-effects (13 [29%]), low perceived risk (ten [22%]), and feeling troublesome about taking daily medications (nine [20%]). Interpretation An incentivised mode of PrEP delivery was moderately well accepted by high risk MSM in Hong Kong. The gap between awareness and their access to PrEP would need to be addressed in the future if programme expansion is considered, since price can be a major deterrent for some eligible people despite the lowered price. Community education on PrEP together with pre-PrEP counselling is crucial for successful implementation. Funding AIDS Trust Fund (MSS 264 R), Hong Kong.

Highlights • As of July 14, 2015, the South Korean outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection has involved 185 secondary infections belonging to three overlapping generations of cases who have contracted the virus almost exclusively in the healthcare environment. • Fomite transmission may explain a significant proportion of the infections occurring in the absence of direct contact with infected cases. • The analysis of publicly available data collected from multiple sources, including the media, is useful for describing the epidemic history of an infectious disease outbreak., Summary Background In May 2015, South Korea reported its first case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in a 68-year-old man with a history of travel in the Middle East. In the presence of secondary infections, an understanding of the transmission dynamics of the virus is crucial. The aim of this study was to characterize the transmission chains of MERS-CoV infection in the current South Korean outbreak. Methods Individual-level data from multiple sources were collected and used for epidemiological analyses. Results As of July 14, 2015, 185 confirmed cases of MERS have been reported in the Korean outbreak. Three generations of secondary infection, with over half belonging to the second generation, could be delineated. Hospital infection was found to be the most important cause of virus transmission, affecting largely non-healthcare workers (154/184). Healthcare switching has probably accounted for the emergence of multiple generations of secondary infection. Fomite transmission may explain a significant proportion of the infections occurring in the absence of direct contact with infected cases. Conclusions Publicly available data from multiple sources, including the media, are useful to describe the epidemic history of an outbreak. The effective control of MERS-CoV hinges on the upholding of infection control standards and an understanding of health-seeking behaviours in the community.

Summary Objectives Human influenza A (H1N1) 2009 has caused severe epidemics in many countries, but its dynamics in spatial and temporal contexts have so far been poorly appreciated. Methods A total of 24,414 laboratory confirmed human influenza A (H1N1) 2009 cases reported from May to September 2009 in Hong Kong were evaluated, using a Geographic Information System (GIS)-based approach. Spatio-temporal clustering was assessed after dividing Hong Kong into 4 geographic sectors, 18 districts and 500 m × 500 m cells. Global Moran's I, Local Moran's I and SaTScan™ were used in the exploration. Results Spatio-temporal clusters first appeared on Hong Kong Island at week 3, alongside multiple foci suggestive of infection nidus introduced from abroad. The clusters grew rapidly and became confluent in urban areas, lasting till week 22. Separately, local clusters emerged in the North representing second or third generation infections, which died down over a relatively short period of time. Conclusion Heterogeneity of spatio-temporal clustering of H1N1 was demonstrated during the epidemic, despite the small area of the territory of Hong Kong. The dynamics could have been shaped by population mobility at a local level. The application of GIS in epidemiology studies can add value to standard surveillance activities.

From 1 May 2009 when the first case of H1N1 in Hong Kong was reported through the end of September 2009, a total of 24,415 successfully geo-coded cases were studied. To investigate the spatial and temporal patterns of H1N1 spread, space-time K-function, implemented on the programme R, was applied. Four geographic regions were delineated in the exploration, but only in two of these, namely, Hong Kong Island and North, were statistically significant results obtained. On Hong Kong Island, clustering was detected from an intercase distance of 5 km and intercase time of 12 weeks onwards, which reflect continuous spread of H1N1 over the whole region without local outbreaks. In North, however, clustering in short intercase time periods suggested the occurence of local outbreaks. In conclusion, though Hong Kong is only a small city in size, the clustering patterns of H1N1 in urban (Hong Kong Island) and rural (North) regions had varied greatly. © 2010 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [name organizer]

Background China periodically has severe ambient particulate matter (PM) pollution, which could cause compromised pulmonary immunity in the population and result in high cardio-respiratory morbidity and mortality. Acknowledging the highly prevalent latent tuberculosis in elderly people, we hypothesise that they are more prone to tuberculosis reactivation in the presence of air pollution. Methods We examined the spatial and temporal association between PM 2·5 concentration and the number of reported cases of tuberculosis in elderly people aged 65 years and older in Hong Kong. Tuberculosis notification data in 2005–07 were collected from the Chinese Government's TB and Chest Service. Monthly and annual PM 2·5 concentration by geographical subdistrict (DCCA) for the corresponding years were derived from satellite images. Age–gender standardised notification rate (SNR) of tuberculosis cases in elderly people was calculated per DCCA/time. Their temporal association with PM 2·5 was examined by dynamic linear regression in R, and spatial association by spatial regression in GeoDa. Findings Among 17 294 new cases of tuberculosis reported in 2005–07, 6879 (40%) cases were in elderly people (2·69 men for every woman). The mean monthly SNR for elderly men was 35·4 per 100 000 persons (range 25·2–45·3), and the mean of mean PM 2·5 in DCCA was 30·5 μg/m 3 (16·1–47·1). Temporally, the SNR for elderly men was associated with PM 2·5 in lag 0, lag −1 (ie, moving PM 2·5 1 month earlier), and lag −4 to −6 months, with the most significant positive association at lag −6 months. However, no temporal association between the SNR for elderly women and PM 2·5 was observed. Spatially, the SNR was associated with PM 2·5 for elderly men in all 3 years but only for women in 2005. Interpretation We detected spatial and temporal associations between cases of tuberculosis in elderly men and PM 2·5 . Tuberculosis reactivation might have occurred after exposure to high PM 2·5 in the environment, as inferred from the lag interval of 6 months revealed in our results. The discrepancy between sexes and the effects of potential confounders such as sunshine duration, income level, and locality would need to be further investigated. Funding Research Grants Council under Theme-based Research Scheme (T32-102/14N).

Background Improved understanding of network structure—one of the driving forces of HIV transmission—could facilitate the design of interventions. We aimed to assess the structure of HIV transmission networks and their relationship to newly diagnosed cases in Hong Kong, where sexual transmission between men prevails. Methods We used HIV gag-pol sequences collected over a 20-year period from all major HIV services in Hong Kong to construct transmission networks. We identified network clusters and decomposed them by modularity if one contained more than half of the connected nodes. We analysed network size, average degree, and epidemiological metrics, and examined sequences of newly diagnosed cases in a cross-sectional study to assess growth of identified clusters. Findings A total of 2352 archived HIV sequences collected in 1994–2013 were retrieved, alongside HIV sequences from 81 cases diagnosed between Aug 4, 2016, and Jan 17, 2017. The transmission network with a density of 1·58% contained 1801 (74%) nodes that were linked to at least one other node. Network degree followed a power law distribution (correlation 0·988). There were 72 dyads and 64 clusters with at least three nodes. The largest connected component contained more than half of the connected nodes (1282 [71%]) and thus was decomposed into 20 clusters. Of 83 clusters included in the analysis, 10 were linked to 37 (46%) new cases. The sizes of incident clusters were significantly larger (p vs 4 [IQR 3-8]) with a higher mean degree (p vs 2·80 [IQR 2·00–4·64]). Clusters with newly diagnosed patients had higher transmission speeds (p vs 0·24 [IQR 0·17–0·44] ppy). Clusters with new cases in 2016 had a higher 3-year cluster incidence in 2013 (p Interpretation Hong Kong's HIV transmission was a preferential attachment process as inferred from the power law degree distribution elicited. The HIV epidemic has grown from existing clusters with large size, degree, and transmission speed. Disassortative age mixing could have predisposed younger individuals to transmission risk from older patients. Funding Research Grants Council of Hong Kong (14103315), AIDS Trust Fund (MSS 229 R, 243 R).

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.

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 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.

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

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.

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.