Hepatitis B burden and population immunity in a high endemicity city - a geographically random household epidemiology study for evaluating achievability of elimination.

This study aimed to provide reference for evaluating the achievability of hepatitis B virus (HBV) elimination in a high endemicity city with universal neonatal vaccination in place for over 30 years. Between September 2018 and October 2020, 2085 citizens from 1143 geographically random households in Hong Kong completed a questionnaire and had blood-testing for HBV markers (anti-HBs, HBsAg, anti-HBc, HBeAg). We evaluated the epidemiology and examined factors associated with HBV exposure, vaccination and chronic diseases. The proportion of households with HBsAg positive index participants was 9.2% (95% CI 7.5%-10.9%). The age- and sex-adjusted HBsAg prevalence was 6.3% (95% CI 5.3%-7.4%), compared to >10% in those born in 1960-1970 and among non-local born citizens, and <1% in people born after introduction of neonatal vaccination. Among 155 HBsAg positive participants, 59% were aware of their infection status with 10% on treatment and 10/150 (6.7%) HBeAg positive. More than 40% (872/2064) tested negative for both HBsAg and anti-HBs, contributed by the lack of immunity in older adults and the waning immunity of vaccines. Hong Kong has remained at high-intermediate HBV endemicity state. The moderate level of anti-HBs positivity and very low treatment coverage (10%) among HBsAg positive participants pose challenges for achieving the HBV elimination target.

Temporal Changes in Sexually Transmitted Infections in a Cohort of Men Who Have Sex with Men Living with HIV: Sex Partner Seeking and Behavioral Correlates.

With "undetectable equals untransmittable," continued engagement in condomless sex has prolonged STI risk in people living with HIV. This study examined the pattern and relationship between STI diagnosis and sex partner-seeking practice over time in a cohort of men who have sex with men (MSM) attending the HIV specialist clinic in Hong Kong. Participants' STI diagnosis record since HIV diagnosis was retrieved and their frequency of seeking sex partners (A) before, (B) after HIV diagnosis, and (C) following extended period (5-10 years), through eight different settings, was assessed in two rounds of survey, along with their risk behavioral profile. Multivariable regression models were employed to study the factors associated with STI diagnosis and partner-seeking frequency, while their temporal relationships over the three time points (A-C) were examined using cross-lagged panel model. Of 345 subjects recruited, STI incidence dropped from 252 to 187 cases/1000 person-years during 2015-2019. Totally 139/212 MSM (66%) had ≥ 1 episode of STI within the 10-year period after HIV diagnosis, giving an 11-20% annual prevalence. The reduced frequency of seeking sex partner was well preserved following diagnosis with a rebound specifically noted in the use of mobile application, the patrons of which were more likely to be co-infected with STI in 2019. Chemsex, concurrent partnership, and casual sex were risk factors shared between frequent partner-seeking practice and STI diagnosis. A robust autoregressive effect for partner-seeking frequency was also identified, and which significantly predicted STI risk in the long term. To enhance HIV care, the co-administration of STI/behavioral surveillance should be emphasized.

Relationship between patient experience and hospital readmission: system-level survey with deterministic data linkage method.

BACKGROUND: Linkage of public healthcare data provides powerful resources for studying from a comprehensive view of quality of care than information for a single administrative database. It is believed that positive patient experiences reflect good quality of health care and may reduce patient readmission. This study aimed to determine the relationship between patient experience and hospital readmission at a system level by linking anonymous experience survey data with de-identified longitudinal hospital administrative admissions data. METHODS: Data were obtained by linking two datasets with anonymised individual-level records from seven largest-scale acute public hospitals over seven geographical clusters in Hong Kong. Selected records in the two datasets involving patient experience survey (PES) (2013 survey dataset) and healthcare utilization (admissions dataset) were used. Following data cleaning and standardization, a deterministic data linkage algorithm was used to identify pairs of records uniquely matched for a list of identifiers (10 selected variables) between two datasets. If patient's record from the survey dataset matched with the hospitalization records in the admissions dataset, they were included in the subsequent analyses. Bivariate analyses and multivariable logistic regression models were performed to evaluate the associations between hospital readmission in the next calendar month and patient experience. RESULTS: The overall matching rate was 62.1% (1746/2811) for PES participants aged 45 or above from the survey dataset. The average score for overall inpatient experience was 8.10 (SD = 1.53). There was no significant difference between matched patients and unmatched patients in terms of their score for the perception of overall quality of care received during hospitalization (X2 = 6.931, p-value = 0.14) and score for overall inpatient experience (X2 = 7.853, p-value = 0.25). In the multivariable model, readmission through the outpatient department (planned admission) in the next calendar month was significantly associated with a higher score given to the overall quality of care received (adjusted OR = 1.54, 95%CI = 1.09-2.17), while such association was absent for readmission through Accident and Emergency department (adjusted OR = 0.75, 95%CI = 0.50-1.12). CONCLUSIONS: This study demonstrated the feasibility of routine record linkage, with the limited intrusion of patients' confidentiality, for evaluating health care quality. It also highlights the significant association between readmission through planned readmission and a higher score for overall quality of care received. A possible explanation might be the perceived better co-ordination between outpatient departments and inpatient service and the well-informed discharge plan given to this group of patients.

Compliance and attitudes of blood donors following transitioning from permanent to 12-month deferral of men who have sex with men in Hong Kong.

BACKGROUND AND OBJECTIVES: Blood safety hinges not just on the scientific rationale for deferral period but potential donors' compliance with the prevailing policy. This study aimed to investigate donors' awareness, attitudes and compliance with the two-phased policy implementation of time-limited deferral for men who have sex with men (MSM) in Hong Kong. MATERIALS AND METHODS: Three rounds of questionnaire survey were conducted between July 2017 and June 2019 covering the periods of pre-implementation (Round A), post-implementation without and with pre-donation questionnaire revision (Round B and C). Chi-square test and multivariable regression analysis were performed. RESULTS: Of 3085 donors recruited, 968, 1036 and 1081 completed the surveys in Round A, B and C, respectively. The non-compliance rate of MSM remained stable at 0·6% (3/497), 0·4% (2/551) and 0·5% (3/587) among male donors in Round A, B and C, respectively. Two MSM donors from Round C complying with the prevailing policy were identified. About two-thirds (60·7%) of respondents from Round B and C were unaware of the policy change. Overall, over 80% were either neutral or positive about the change. CONCLUSION: Our study showed a consistently low non-compliance rate of MSM over the three periods. The generally high level of acceptance of time-limited deferral among donors lends support to science-based policy development to protect blood safety. The identification of compliant MSM donors suggests that the 12-month deferral is effective and acceptable to MSM. With a deferral period far exceeding the window period, it is a step towards a more equitable policy.

A comparative analysis of behaviors and sexual affiliation networks among men who have sex with men in Hong Kong.

In Hong Kong, men who have sex with men (MSM) account for a significant proportion of HIV infections. While perceived as a hidden population, they constitute a distinct social network shaped by their differential use of unique channels for sex partnership. To characterize their pattern of connectivity and association with high-risk sexual behaviors, 311 MSM were recruited via saunas and the internet to participate in a questionnaire survey. Internet recruits were younger, and many (31/43) were solely reliant on the internet to seek sex partners, while visiting a similar number of venues as the sauna recruits (p = 0.98). Internet users generally had a high frequency of unprotected anal intercourse (UAI). MSM who had visited only a single venue reported more UAI with their regular partners (adjusted OR 6.86, 1.88-24.96) and sought fewer casual partners than those frequenting multiple venues (adjusted OR 0.33, 0.19-0.60). This study provides evidence for the heterogeneity of the sexual affiliation networks of MSM in Hong Kong. High HIV risk of UAI could be offset by fewer casual partners in certain venues, the implications of which would need to be explored in longitudinal studies. Methodologically, internet sampling was very efficient in identifying sex networking venues, while internet recruits gave a high retention rate for updating profiles. However, sampling at high centrality saunas did not necessarily identify the MSM-affiliating venues in the networks efficiently. The sampling strategy of MSM survey should therefore be objective-driven, which may differ for health message dissemination and social marketing, versus HIV surveillance or risk assessment.

Sex networking of young men who have sex with men in densely connected saunas in Hong Kong.

BACKGROUND: Some men who have sex with men (MSM) meet and have sex with male partners at gay saunas, the connections between which are little explored for designing HIV prevention measures. This study aims to describe the network configuration of gay saunas and explore its relationship with risk behavior of MSM in the respective sauna communities, in the city of Hong Kong. METHODS: Using venue-based sampling, 205 MSM were recruited in 8 saunas in July 2011 for a cross-sectional anonymous questionnaire survey. A network of saunas was constructed based on the proportion of clients shared between them. Core saunas with higher intensity of linkages were delineated from core-periphery analysis. Men who have sex with men in core saunas were compared with those in peripheral ones in terms of their demographics and risk behavioral profiles. RESULTS: Eight core saunas were differentiated from a highly connected sauna network, consisting of 13 saunas with a diameter of 2. Men who have sex with men visiting core saunas were more likely to be younger and users of the Internet for sex networking (odds ratio, 5.43; 95% confidence interval, 1.84-16.01). On average, they visited 1.7 saunas and had 2.6 sauna partners over a 1-month period, which were both significantly higher than those for MSM in peripheral saunas. However, there was no association between having unprotected anal sex and visiting core saunas. Sauna affiliation patterns were age dependent and geographically related. CONCLUSIONS: Saunas were not homogeneously connected with each other. Prioritization may be considered so that public health interventions can be targeted at saunas in denser networks. An assortative mixing in age among MSM in sauna community informs planning for client-specific venue-based prevention programs.

Point-of-care hepatitis C reflex testing and treatment referral in methadone clinic settings in Hong Kong-a pilot study.

Objectives: People who inject drugs (PWID) constitute a population group with a high hepatitis C virus (HCV) burden. With the objectives of assessing the HCV prevalence in PWID and determining the proportion requiring treatment who could be linked to care, this study piloted onsite reflex HCV testing at low threshold methadone clinics, with prompt referral of HCV RNA-positive participants for treatment. Methods: This was a prospective study on methadone clinic attendees in Hong Kong. Questionnaires were completed, finger-prick anti-HCV rapid testing was performed, and positive blood samples were collected for laboratory HCV RNA testing. The proportions of participants along the cascade of HCV care were calculated. Results: In 2021-2022, after 14 evening screening sessions at three methadone clinics, 86 of 354 regular attendees (24%) were recruited. The anti-HCV prevalence was 63% (54/86, 95% confidence interval 52-73%), with 78% (42/54) testing positive for HCV RNA and 79% (33/42) successfully referred. Almost all (31/33) referred participants received direct-acting antiviral (DAA) treatment, 94% (29/31) with full treatment compliance; 55% (16/29) of these compliant participants achieved a sustained virological response, while the remainder had not received post-treatment testing. Conclusions: The use of a simplified testing algorithm in the setting of substitution treatment services, incorporating reflex HCV testing, could be an effective strategy for contributing towards the micro-elimination of HCV in PWID.

Seroepidemiology of hepatitis A and B in the general population in Hong Kong: protocol of a cross-sectional survey using spatial sampling in a highly urbanised city.

INTRODUCTION: Differences in immunisation policies have significantly reshaped the epidemiology of hepatitis A and B in the population. Assessment of the susceptibility and transmission potential of these two types of vaccine-preventable hepatitis would enhance the capacity of public health authorities for viral hepatitis elimination. Focusing on Hong Kong, the objectives of this study comprise the determination of the population-level seroprevalence of hepatitis A and B and an examination of the risk factors for virus transmission and the population impacts of vaccinations. METHODS AND ANALYSIS: This is a cross-sectional household survey on hepatitis A and B. By using socially homogeneous building groups as sampling frame, eligible members of 1327 spatially selected households would be invited to complete a questionnaire and provide blood samples for serological testing (anti-hepatitis A virus, hepatitis B surface antigen, hepatitis B surface and core antibody). The main measures comprise a set of metrics on the prevalence of hepatitis A and B. Analysis would be conducted to examine the association of risk factors with the tested markers and describe the attitudes towards viral hepatitis vaccination. ETHICS AND DISSEMINATION: Ethical approval from the Joint Chinese University of Hong Kong-New Territories East Cluster Clinical Research Ethics Committee, and approval for laboratory safety from the Chinese University of Hong Kong have been obtained. The study results will be presented in scientific forums to update on the epidemiology of hepatitis A and B and inform the development of new vaccination strategies in Hong Kong. TRIAL REGISTRATION NUMBER: NCT04371276.

Changes of sexual risk behaviors and sexual connections among HIV-positive men who have sex with men along their HIV care continuum.

BACKGROUND: While HIV incidence among men who have sex with men (MSM) is increasing in Hong Kong, unprotected sex apparently remains prevalent among those infected but virally non-suppressed. Little is known about how sexual behaviours and sexual connections may change among MSM along their HIV care continuum. METHODS: In this retrospective cross-sectional study, HIV-positive MSM attending the largest HIV specialist clinic in Hong Kong between October and December 2014 were invited to complete a self-administrated structured questionnaire. Their behavioural profile and partner sourcing patterns during the one-year period respectively (a) before HIV diagnosis, (b) after HIV diagnosis, (c) after initiation of antiretroviral treatment and (d) preceding the survey were examined. RESULTS: Of 345 recruited MSM, 304 (88.1%) had treatment initiated and 272 (78.8%) had viral load suppressed. In the first year after HIV diagnosis, the proportion reporting inconsistent condom use dropped from 47.0% to 17.5% (p<0.05) and from 49.6% to 17.8% (p<0.01) for anal sex with main and casual partners respectively. Except for mobile applications, usage of most sex-networking venues decreased significantly after diagnosis. Inconsistent condom usage rate remained at around 20% after treatment initiation and viral load suppression, but the frequency of use of sex-networking venues further varied among virally suppressed MSM. CONCLUSIONS: Most HIV-positive MSM had persistently low level of sexual risk behaviours along their care continuum and achieved viral load suppression, conferring a general reduction of secondary transmission risk in Hong Kong. To increase the effectiveness of Treatment as Prevention strategy, uptake of HIV testing for undiagnosed HIV-positive MSM shall be emphasised.

Distribution of reported syphilis cases in South China: spatiotemporal analysis.

There was a varied spatial distribution of reported syphilis cases across cities in South China. This study aims to identify and describe spatiotemporal clusters of primary and secondary syphilis (P/S) cases in this region. Reported syphilis cases in Guangdong Province, China, from January 2014 to June 2015 were collected from the national centralized reporting system. Spatiotemporal clusters of P/S were identified and cross-validated by calculating local Moran's I, performing hotspot analysis (Getis-Ord Gi*), and constructing a discrete Poisson model in SaTScan. Reported cases within and outside the clusters were compared by bivariable and multivariable logistic regression. Out of 17,691 reported P/S cases, 11% were in the identified spatiotemporal clusters. The monthly P/S notification rate (per 100,000 persons) ranged between 0.6 and 1. The identified clusters were located in 14, out of 126, counties in eight, out of 21, cities. Cases of older age, living in rural area and taking self-initiated syphilis test were more likely to be in the clusters. Some areas bore a greater burden of P/S in Guangdong Province. Routine spatiotemporal analysis of P/S cases may be useful for enhancing syphilis control programs by strategic location-based service planning.

A GIS-based assessment of environmental influences on allergy development in children.

This study aims to assess potential environmental influences on allergy development in children. Based on a parent-completed questionnaire survey administered in Hong Kong in 2003 in accordance with the International Study of Asthma and Allergies in Childhood protocol, the prevalence and incidence of asthma and rhinoconjunctivitis of 508 preschool children aged 4 to 6 years in Yuen Long District were determined and a range of indoor and outdoor environmental factors were assessed. Exposure to moisture and mold in the first year of life increased the risk of asthma (adjusted odds ratio [aOR] = 2.56; 95% confidence interval [CI] = 1.40-4.68) and rhinoconjunctivitis (aOR = 2.09; 95% CI = 1.15-3.80). Current maternal smoking was also associated with a higher prevalence of asthma (aOR = 2.00; 95% CI = 1.04-3.84). No association was observed between outdoor traffic-related air pollutants and the prevalence of the allergic conditions. Indoor home environments had a stronger influence on allergy development, whereas exposure to traffic-related external environment gave a variable effect, the significance of which would be difficult to be substantiated.