Publications by authors named "Ngai Sze Wong"

Background: Human papillomavirus (HPV) infection is prevalent among people who are sexually active. This study aimed to compare the levels of behavioral intention to receive free clinician-collected and self-collected samples for HPV DNA testing and its determinants between heterosexual males and females in Hong Kong, China.

Methods: This is a secondary analysis of a territory-wide survey conducted in Hong Kong between May 2021 and March 2022.

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Background: Exposure risk was shown to have affected individual susceptibility and the epidemic spread of COVID-19. The dynamics of risk by and across exposure settings alongside the variations following the implementation of social distancing interventions are understudied.

Objective: This study aims to examine the population's trajectory of exposure risk in different settings and its association with SARS-CoV-2 infection across 3 consecutive Omicron epidemic waves in Hong Kong.

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Purpose: To detect otherwise undiagnosed asymptomatic sexually transmitted infection (STI), and for estimating prevalence among men who have sex with men (MSM).

Methods: In this community-based study in Hong Kong, adult MSM were recruited. After completion of an online survey, free multi-anatomic sites self-sampling kits (urine specimens, pharyngeal and rectal swabs) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) tests were delivered to requesting participants.

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Pre-exposure prophylaxis (PrEP) use has been shown to be effective for HIV prevention in men who have sex with men (MSM). PrEP use coverage aside, maintenance of high PrEP adherence is crucial in ensuring the achievement of HIV prevention. In this PrEP implementation study in Hong Kong, we examined the patterns of PrEP use in MSM and evaluated their association with prevention-effective adherence for HIV prevention.

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Objectives: While the plausible role of ambient particulate matter (PM) exposure in tuberculosis (TB) reactivation has been inferred from experiments, epidemiologic evidence is lacking. We examined the relationship between ambient PM concentration and pulmonary TB (PTB) in an intermediate TB endemicity city dominated by reactivation diseases.

Methods: Spatio-temporal analyses were performed on TB notification data and satellite-based annual mean PM concentration in Hong Kong.

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Article Synopsis
  • Post-COVID-19, there's an increased risk of mpox infection for vulnerable groups like men who have sex with men (MSM) and people living with HIV, especially as international travel resumes.* -
  • In Hong Kong, free mpox vaccinations target high-risk individuals, revealing that while many MSM feel a strong need to protect their partners, stigma around mpox symptoms is also a significant concern.* -
  • Although MSM in HIV care are less sexually active than those at vaccination sites, they report higher recent STI diagnoses and perceived exposure risks, indicating the need for accessible vaccination options for varied risk behaviors.*
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Without protective immunity, recurrent sexually transmitted infections (STI) could occur. In this study, we retrospectively collected STI diagnosis records from public STI clinics attended by an average of 6,000 male patients annually in Hong Kong in 2009-2019. We estimated the prevalence of three bacterial STI (syphilis, chlamydia and gonorrhoea) coinfection from 2009 to 2019, and examined the factors associated with coinfection in 2014/15 and repeat infection in 2009-2019.

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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.

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Timely detection of an evolving event of an infectious disease with superspreading potential is imperative for territory-wide disease control as well as preventing future outbreaks. While the reproduction number (R) is a commonly-adopted metric for disease transmissibility, the transmission heterogeneity quantified by dispersion parameter k, a metric for superspreading potential is seldom tracked. In this study, we developed an estimation framework to track the time-varying risk of superspreading events (SSEs) and demonstrated the method using the three epidemic waves of COVID-19 in Hong Kong.

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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.

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Hong Kong is an Asia-Pacific City with low incidence but periodic local outbreaks of dengue. A mixed-method assessment of the risk of expansion of dengue endemicity in such setting was conducted. Archived blood samples of healthy adult blood donors were tested for anti-dengue virus IgG at 2 time-points of 2014 and 2018/2019.

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Background: Regular HIV and sexually transmitted infection (STI) testing for men who have sex with men (MSM) is an important means of infection prevention, the adoption of which remains suboptimal in the community.

Objective: On the hypothesis that engagement plays an important role in sexual health monitoring, this study aimed to pilot-test internet-based HIV and STI testing with self-sampling to enhance engagement of MSM with regular testing.

Methods: This 1-year cohort study was conducted on HIV-negative MSM aged 18 years or older.

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Background: The COVID-19 Omicron BA.2 epidemic wave in Hong Kong peaked in the first quarter of 2022. Following the implementation of stringent public health measures, the daily number of reported cases fell from over 50,000 to below 2000.

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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.

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Objectives: To assess impacts of early detection and prompt antiretroviral therapy (ART) on the latest epidemiologic situation to inform intervention strategy.

Methods: We analysed data from two clinical cohorts in Hong Kong where sexual transmission accounted for the majority of HIV infections. The two cohorts comprised patients newly diagnosed in 2007-2008 and 2016-2018 respectively.

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In a cohort of persons living with HIV in Hong Kong, surrogate virus neutralization testing for COVID-19 yielded a median level of 89% after the third dose of an inactivated COVID-19 vaccine, compared with 37% after the second dose. These results support using a 3-dose primary series for enhanced immune protection.

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Background: Worldwide, the COVID-19 pandemic has disrupted influenza seasonality and impacted influenza vaccination behaviours. This study examines the patterns of influenza vaccination uptake in nurses during the pre-pandemic seasons and amidst the pandemic in 2020/21 in subtropical Hong Kong.

Methods: In April 2021, a cross-sectional survey was conducted in practising and student nurses.

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Background: The adaptive immune responses of COVID-19 patients contributes to virus clearance, restoration of health and protection from re-infection. The patterns of and the associated characteristics with longitudinal neutralising antibody (NAb) response following SARS-CoV-2 infection are important in their potential association with the population risks of re-infection.

Methods: This is a longitudinal study with blood samples and clinical data collected in adults aged 18 or above following diagnosis of SARS-CoV-2 infection.

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Objective: People with HIV (PWH) co-infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are at higher odds of severe diseases. Whereas the immunogenicity of mRNA vaccine and adenovirus-vectored vaccine was similar between PWH in stable condition and healthy adults, the effects of inactivated vaccines are not known.

Design: Prospective longitudinal observational study in real-world setting.

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Exposure setting is crucial in the formation and propagation of SARS-CoV-2 transmission clusters. In this cohort study, transmission networks of 2 waves were differentiated by exposure setting using territory-wide surveillance data with clinical and laboratory records in Hong Kong. Characteristically, the first wave had resulted from imported cases followed by local transmissions, while the second wave was constituted primarily by local infections.

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