Dynamicity of HIV Pre-exposure Prophylaxis Usage Pattern and Association with Executed Adherence in MSM: An Implementation Study in Hong Kong.

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. In January 2020-June 2021 in Hong Kong, 312 recruited MSM (median 30 years old) were followed up for 1 year, with HIV and creatinine testing, consultation, and PrEP refill. No HIV breakthrough infection was observed. As a measure of prevention-effective adherence, executed adherence (EA) was expressed as the proportion of days with HIV risk that were protected by PrEP and/or condom in 6 months. In 65,585 diary entries of 215 MSM, the median proportion of EA achieved was 89% (IQR 84-93%). Three latent classes of PrEP users were identified by latent class analysis. Taking Class 1 "daily dominant PrEP" (n = 113, 53%) as reference, Class 2 "episodic PrEP" (n = 76, 35%) was adopted by MSM with less sexual activity, had less PrEP refill and lower EA level, while Class 3 "mixed PrEP schedule" (n = 26, 12%) MSM were more sexually active but with a similar EA level. The study findings showed varied and dynamic PrEP usage patterns in the real-world setting. Strategies for promoting adherence are needed to ensure the maintenance of high EA level among PrEP-using MSM especially those on episodic PrEP schedule.

Self-sampled multi-anatomic site testing for uncovering the community burden of undiagnosed Chlamydia trachomatis and Neisseria gonorrhoeae infection in men who have sex with men.

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. Factors associated with STI positivity were analyzed in logistic regression. RESULTS: From September 2021 to October 2022, 712 MSM were recruited, with 86% aged 18-39, and 16% reported history of chemsex engagement. A majority (81%) had previously undergone HIV testing, 68% had ever tested for STI, and 35% previously diagnosed with STI. Totally 428 (60%) had requested self-sampling kits, and 276 (39%) returned collected samples. Among participants who returned the samples, about half had never been tested in the past and had no history of STI. Overall 21% tested positive for CT and/or NG (CT/NG)-CT positive 16% and NG positive 7%. By anatomic site, 16% of rectal swabs, 7% of pharyngeal swabs, but just 3% of urine specimens were CT/NG positive. The prevalence of CT/NG was not significantly different by history of STI diagnosis and testing. CONCLUSION: Self-sampled STI testing is a potentially useful means for enhancing uptake of screening in MSM in the community, which could uncover otherwise undiagnosed asymptomatic infections. Internet-based self-sampling for STI testing could complement the current clinic-based STI testing for supporting epidemiologic evaluation of STI control in the community.

Coinfection and repeat bacterial sexually transmitted infections (STI) - retrospective study on male attendees of public STI clinics in an Asia Pacific city.

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. We observed an increasing coinfection prevalence in male attendees with bacterial STI over the years, which reached the highest level of 15% in 2019. Among 3,698 male patients in 2014-2015, chlamydia/gonorrhoea coinfection was the commonest among all coinfections (77%). Factors such as young age (29 or below), HIV-positive status, and a history of concurrent genital warts/herpes were positively associated with coinfection in 2014/15 in multivariable logistic regression. Of all male patients with STI coinfection in 2014/15, those of age 30-49 and who self-reported as men who have sex with men (MSM) were more likely to have been repeatedly infected in 2009-2019. The results support the implementation of regular multi-STI testing as an STI control strategy for selected communities like MSM and people living with HIV.

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.

Shifts of SARS-CoV-2 exposure settings in the transmission clusters of 2 epidemic waves in Hong Kong.

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. With a 4-fold higher caseload, the second wave featured predominance of epidemiologically linked, local, older and asymptomatic patients with higher viral loads and shorter inpatient days. The 1028 transmission clusters formed 155 cascades composing at least two clusters. Daily and social activities were exposure settings that bridged clusters while residences usually terminated transmission cascades. Regulatory restrictions on social activities extinguished cluster formation in bars, but shifted to private parties in the second wave. The results confirmed that strategic interventions targeting exposure settings could achieve effective epidemic control.

Three-Dose Primary Series of Inactivated COVID-19 Vaccine for Persons Living with HIV, Hong Kong.

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.

Awareness of HIV functional cure and willingness in participating in related clinical trials: comparison between antiretroviral naïve and experienced men who have sex with men living with HIV.

BACKGROUND: Human immunodeficiency virus (HIV) functional cure is a novel biomedical strategy characterized by sustained viral suppression without the need for life-long medications. The attitude of people living with HIV (PLHIV) towards functional cure and clinical trials are understudied. We aimed to examine the awareness and levels of anticipation for HIV functional cure among men who have sex with men (MSM) living with HIV, and their willingness to join trials as differentiated by their antiretroviral treatment status. METHODS: MSM living with HIV with and those without treatment history were recruited from Hong Kong's HIV specialist clinics. Self-administered questionnaires covering behavioral profile, perceived impact of HIV cure, attitude towards HIV functional cure and related clinical trials were collected. Clinical data were separately transcribed. Determinants of perceptions and attitudes were identified by logistic regression models. RESULTS: Of 356 MSM living with HIV recruited, less than half (42%) were aware of HIV functional cure, but they had a high level of anticipation for it. Treatment-experienced participants were more likely to be aware of HIV functional cure. Awareness was associated with continued engagement in sexual activities after HIV diagnosis and sexually transmitted infection (STI) diagnosis. Higher anticipation was observed among older MSM living with HIV but it was negatively associated with one's awareness. Over 90% were willing to join functional cure trials, especially those who had previously been diagnosed with STI and had engaged in chemsex in the past year. Advice from healthcare professional was an important factor considered by those willing to join clinical trials. Younger, better educated MSM, and those with lower CD4 counts were more concerned about potential risk of AIDS and potential complications upon trial participation. CONCLUSIONS: MSM living with HIV, especially those sexually active, showed positive attitude towards functional cure and willingness to join related clinical trials despite low awareness. To enhance preparedness for HIV functional cure trials, community education, updated information and appropriate medical advice would be needed. Safety is a major concern for potential enrollees in HIV functional cure trials.

Impact of pre-event testing and quarantine on reducing the risk of COVID-19 epidemic rebound: a modelling study.

BACKGROUND: With the evolving growth of the COVID-19 epidemic, travel restriction policies would need to be adjusted accordingly. Prohibition of mass event may be relaxed for social and economic benefits when virus transmission stops but could bear the risk of epidemic rebound. Against the background of the varied SARS-CoV-2 prevalence internationally, we modelled the potential impacts of pre-event interventions on epidemic risk of holding a mass event when COVID-19 is under control. METHODS: We developed a mathematical model of SARS-CoV-2 transmission in Guangdong Province, China, where local virus transmission ceased to occur. A large-scale international trade fair was assumed to be held, with influx of people from overseas and rest of China over a short period of time, who participated for 2-week. Scenarios of pre-event intervention (none, quarantine arrangement and polymerase chain reaction (PCR) testing for participants) were compared. The influence of contact pattern, SARS-CoV-2 prevalence outside the province and China, and testing coverage were examined in sensitivity analyses. RESULTS: In basecase scenario (no event), the epidemic has been under control since March 2020. The event would lead to the detection of 1% more confirmed cases by 31 July when community contact rate increases to pre-epidemic level. In event scenario without additional interventions, there would be 599 (93%) more new infections comparing with basecase scenario. To avert new infections, quarantining all participants before the event would be the most effective strategy, followed by quarantining all overseas participants and testing all other participants, and testing all participants before the event and on day 7. However, testing strategy is likely to be affected by the SARS-CoV-2 prevalence outside the event province. CONCLUSIONS: Pre-event interventions are effective for reducing the risk of epidemic rebound caused by an international large-scale event. Universal testing for participants is likely to be an effective and feasible intervention.

Low level of dengue infection and transmission risk in Hong Kong: an integrated analysis of temporal seroprevalence results and corresponding meteorological data.

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. Data on the monthly notified dengue cases, meteorological and vector (ovitrap index) variables were collected. The dengue virus (DENV) IgG seroprevalence of healthy adults in 2014 was 2.2% (95%C.I. = 1.8-2.8%, n = 3827) whereas that in 2018/2019 was 1.7% (95%C.I. = 1.2-2.3%, n = 2320). Serotyping on 42 sera in 2018/2019 showed that 22 (52.4%) were DENV-2. In 2002-2019, importation accounted for 95.3% of all reported cases. By wavelet analysis, local cases were in weak or no association with meteorological and vector variables. Without strong association between local cases and meteorological/vector variables, there was no evidence of increasing level of dengue infection in Hong Kong.

Modelling the impact of a sex work crackdown on syphilis transmission among female sex workers and their clients in South China.

OBJECTIVE: To estimate the potential effects of an intense sex work crackdown on syphilis transmission in Guangdong Province, China. METHODS: We developed a deterministic compartmental model of syphilis transmission among female sex workers (FSW) and their male clients in Guangdong Province, China. We based model assumptions on census data and scientific literature, and we fitted the model to sentinel surveillance estimates of syphilis prevalence (positive results in both treponemal and non-treponemal tests) among FSW between 2009 and 2013. We estimated the impact of an intense sex work crackdown in 2014 by comparing the number of new syphilis infections between 2014 and 2020 in crackdown versus basecase (no crackdown) scenarios. In modelling scenarios, we examined main crackdown mechanisms of impact, including changed number of FSW engaging in sex work, reduction of weekly transactions, condom usage rate and syphilis diagnosis rate. RESULTS: In the basecase, predicted syphilis prevalence in FSW decreased from 2% in 2014 to 0.4% in 2020. In crackdown scenarios, syphilis incidence was predicted to transiently decrease and then to rebound relative to basecase levels a few years later. Shorter crackdowns led to higher, faster rebounds. CONCLUSIONS: Short-term intense crackdowns may exacerbate syphilis transmission among FSW and further marginalise an already vulnerable group. This study provides a quantitative, infection-related basis for changing sex work policies to reduce harms.

Distribution of molecular strains of Mycobacterium tuberculosis in an intermediate burden Asia Pacific city.

Hong Kong is an intermediate tuberculosis (TB) burden city in Asia Pacific with slow decline of case notification in the last decade. By 24-loci mycobacterial interspersed repetitive units - variable number of tandem repeats genotyping, we examined 534 Mycobacterium tuberculosis isolates collected from culture-positive hospitalised TB patients in a 1.7 million population geographic region in the city. Overall, 286 (75%) were classified as Beijing genotype, of which 216 (76%) and 59 (21%) belonged to modern and ancient sub-lineage, respectively. Only two cases were genetically clustered while spatial clustering was absent. Male gender, permanent residency in Hong Kong and born in Hong Kong or Mainland China were associated with Beijing genotype. The high prevalence of Beijing modern lineage was similar to that in East Asia, which reflected the pattern resulting from population migration. The paucity of clustering suggested that reactivation accounted for most of the TB disease cases, which was and echoed by observation that half were 60 years old or above, and the presence of co-morbid medical conditions. The predominance of reactivation TB cases in intermediate burden localities implies that the detection and control of latent TB infection would be the major challenge in achieving TB elimination.

A survey of the involvement of primary care doctors in HIV prevention and care in a low-prevalence, high-income setting.

BACKGROUND: In high-income countries with a low HIV prevalence, primary care doctors are likely the first point of medical contact for people at high risk of HIV. One of the key factors for successful implementation of preventive measures is the cooperation of primary healthcare providers. Hong Kong's population mostly seek primary care in the private sectors. Our study evaluated the involvement of private primary healthcare providers in HIV prevention and care. METHODS: A cross-sectional postal structured questionnaire was administered to 1102 private primary care doctors in Hong Kong in December 2017. Responses were received via postal mail, fax or online. Non-respondents received a phone-call reminder to complete the survey. Descriptive analyses were performed for all the question items. Chi-square test was used to assess the association between participants' level of involvement in HIV prevention and care and their demographics and medical practice characteristics. RESULTS: The response rate was 17.9% (197/1102). Most of the respondents were Chinese (95%) and have obtained their primary medical qualifications in Hong Kong (72%). More than half of the doctors have practiced in the private sector for more than 20 years (54%). Six aspects were used to evaluate practices or involvements in HIV prevention or care: Most of the responding doctors had offered advice (61%) and/or HIV test (76%) to patients with high-risk behaviors. However, fewer doctors had diagnosed HIV (27%), provided care for HIV positive patients (21%), reported HIV cases (19%) or prescribed antiretrovirals (4%). Nine (4.5%) did not answer all six questions on their practices or involvements in HIV prevention or care. The remaining respondents were then categorized into no/low involvement group and high involvement group. Overall,71% had no/low involvement (133/188) compared to 29% who had high involvement (55/188). Factors associated with high involvement included being in the 50-59 age group (OR: 2.48, 95% CI: 1.12-5.5), and belonging to a large practice (OR: 3.16, 95% CI: 1.4-7.12). CONCLUSIONS: Overall, most private primary care doctors in Hong Kong have no or low involvement in HIV prevention and care. However, most were willing and experienced in providing general preventive services, such as HIV testing and advice.

Antiviral Therapy for Hepatitis B Prevents Liver Injury in Patients With Tuberculosis and Hepatitis B Coinfection.

BACKGROUND: Chronic hepatitis B virus (HBV) infection increases the risk of liver injury in patients who undergo antituberculosis treatment. It is uncertain whether antiviral treatment for HBV at the time of tuberculosis diagnosis would reduce the risk of liver injury. METHODS: We performed a population-level, retrospective, cohort study that involved all patients with tuberculosis-HBV coinfection treated in public hospitals in Hong Kong over a 16-year period. Patients who received antiviral treatment at the time of tuberculosis diagnosis were considered "patients on antiviral therapy." A multivariable Cox proportional hazards model was used to determine the adjusted hazard ratio of hospitalization due to drug-induced liver injury within 1 year in patients on antiviral therapy, adjusting for the propensity score. RESULTS: Of 3698 patients with tuberculosis-HBV coinfection, 488 (13.2%) were patients on antiviral therapy. Of the remaining 3210 patients, 446 (13.9%) started antiviral therapy within 1 year of tuberculosis diagnosis. Adjusting for the propensity score, patients on antiviral therapy had a lower risk of hospitalization due to drug-induced liver injury compared with those not on treatment (adjusted hazard ratio, 0.44; 95% confidence interval .26-.72). Compared with patients who started antiviral therapy within 1 year of tuberculosis diagnosis, patients on antiviral therapy also had a lower risk of hospitalization due to drug-induced liver injury and a lower risk of liver-related mortality. CONCLUSIONS: We show that antiviral treatment for HBV given at the time of tuberculosis diagnosis reduced the risk of liver injury in tuberculosis-HBV coinfected patients.

A Nationwide Spatiotemporal Analysis of Syphilis Over 21 Years and Implications for Prevention and Control in China.

Syphilis control programs have been scaled up due to the substantial burden in China. We analyzed syphilis incidence according to demographic, spatiotemporal, and economic factors. The increasing latent syphilis diagnoses and declining congenital syphilis suggest the effectiveness of scale-up screening. However, primary and secondary cases persist, especially in inland provinces.

Abrupt Subsidence of Seasonal Influenza after COVID-19 Outbreak, Hong Kong, China.

The onset of the 2019-20 winter influenza season in Hong Kong coincided with the emergence of the coronavirus disease epidemic in neighboring mainland China. After widespread adoption of large-scale social distancing interventions in response to the impending coronavirus disease outbreak, the influenza season ended abruptly with a decrease to a low trough.

Partner Notification Among Persons With Early Syphilis in Shenzhen, China, 2011-2017: Implications for Practice and Policy.

BACKGROUND: Partner notification (PN) is an essential component of syphilis control and is recommended by Chinese Sexually Transmitted Disease guidelines. However, in China, studies examining local practice are limited. This study evaluated PN outcomes among persons with early syphilis infection in an urban district in China. METHODS: From 2011 to 2017, persons diagnosed with early syphilis were asked to participate in an evaluation of supportive patient referral partner services for all recent sex partners, and the contact and case finding indices were determined in Nanshan District, Shenzhen, China. RESULTS: During the study period, 642 index patients with early syphilis reported 1749 sex partners. Of those partners, 678 were potentially contactable and 525 (30%) were contacted. The overall contact index was 0.82. Among the 1749 partners reported, 1108 (63%) were described as casual partners, and only 37 (3%) were contacted (contact index 0.13) compared with 641 partners who were either spouses and regular partners (contact index, 1.37). Among those 525 partners contacted, 418 (80%) were tested, and 205 (39%) were diagnosed with and treated for syphilis. Among those, 9 (4%) were primary, 26 (13%) were secondary, 16 (8%) were early latent, and 154 (49%) were other syphilis infections. The overall case finding index was 0.29. CONCLUSIONS: There is a need to improve PN practices in China, which include developing operational guidelines of PN and to develop and evaluate novel PN ways like using Internet-based strategy.

Molecular epidemiology of acute HCV infection in HIV-positive patients from Hong Kong, Taipei, Tokyo.

BACKGROUND: Acute hepatitis C virus (HCV) infections have been increasingly reported among human immunodeficiency virus (HIV)-positive men who have sex with men (MSM) in the Asia-Pacific region. It remains unknown whether international network of HCV transmission has occurred in this region. METHODS: HIV-positive patients with acute HCV infection, defined as HCV seroconversion within a year or documented acute hepatitis with seroconversion, diagnosed in Hong Kong, Taipei and Tokyo during 2010-2016 were included in this molecular epidemiology study. The NS5B region of the HCV genome (365 bp) was amplified using nested polymerase chain reaction and sequenced. RESULTS: Of 234 HIV-positive patients with acute HCV infection, all were male with 94% being MSM. At the diagnosis of acute HCV infection, 73.5% had concurrent sexually transmitted diseases and 88.0% were receiving combination antiretroviral therapy. The most prevalent HCV genotype was 3a, 2a and 1b in Hong Kong, Taipei and Tokyo respectively. Nine independent clusters belonging to five genotypes (1b, 2a, 2c, 3a and 6a) were identified, each of which occurred in one city without overlapping except for one 3a sequence from Taipei that was closely related genetically to the Hong Kong cluster. CONCLUSIONS: No international network of HCV transmission was identified among HIV-positive patients in the three Asia-Pacific cities. The transmission dynamics of sexually acquired HCV differed by city, but the risk of intercity clustering should not be ignored.

HIV Linkage to Care and Retention in Care Rate Among MSM in Guangzhou, China.

Quantifying HIV service provision along the HIV care continuum is increasingly important for monitoring and evaluating HIV interventions. We examined factors associated with linkage and retention in care longitudinally among MSM (n = 1974, 4933 person-years) diagnosed and living in Guangzhou, China, in 2008-2014. We measured longitudinal change of retention in care (≥2 CD4 tests per year) from linkage and antiretroviral therapy initiation (ART). We examined factors associated with linkage using logistic regression and with retention using generalized estimating equations. The rate of linkage to care was 89% in 2014. ART retention rate dropped from 71% (year 1) to 46% (year 2), suggesting that first-year retention measures likely overestimate retention over longer periods. Lower CD4 levels and older age predicted retention in ART care. These data can inform interventions to improve retention about some subgroups.