Regular Testing of HIV and Sexually Transmitted Infections With Self-Collected Samples From Multiple Anatomic Sites to Monitor Sexual Health in Men Who Have Sex With Men: Longitudinal Study.

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. A designated website was set up to enable participants to make appointments for baseline and follow-up visits at 3-monthly intervals. On-site blood sampling was performed for HIV and syphilis tests, along with self-collection of pharyngeal swabs, rectal swabs, and urine samples for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) testing. Full engagement, as defined by having made at least 3 visits over a 6-12 months' follow-up period, was compared with partial engagement in the bivariable logistic regression model. RESULTS: Between August 2019 and October 2020, 204 MSM were recruited, after the exclusion of 2 baseline HIV-positive MSM. The majority (189/204, 92.7%) were Chinese, the median age was 31 (IQR 26-39) years, and 58.0% (116/200) had experience with pre-exposure prophylaxis (PrEP) at baseline. Full engagement (146/204, 71.6%) was associated with incident STI during the follow-ups (odds ratio [OR] 4.23, 95% CI 1.63-10.94), seeking a medical referral after STI detection (OR 10.25, 95% CI 3.25-29.79), and a synchronized schedule of HIV and STI testing with PrEP visits (OR 51.85, 95% CI 19.30-139.34). No incident HIV was detected in the follow-up period. At baseline, the overall STI (CT, NG, or syphilis) prevalence was 30%, with CT at 18%, NG at 13%, and syphilis at 5%. During follow-up, the incidences were 59.08/100 person-years (py) for any STI, 33.05/100 py for CT, 29.86/100 py for NG, and 10.4/100 py for syphilis. The detection rates of CT and NG in urine samples were lower than with pharyngeal swabs and rectal swabs. The scores for convenience, confidence of correct sampling, and accuracy of self-sampling were high (7 to 8 out of 10). CONCLUSIONS: Both baseline prevalence and incidence of STI were high among MSM engaged in regular testing. A high degree of engagement in regular STI and HIV testing was positively associated with incident STI, history of health-seeking behaviors, and perceived convenience of self-sampling. Self-sampling could be introduced as a means of enhancing engagement in regular HIV and STI testing.

Trajectory patterns of SARS-CoV-2 neutralising antibody response in convalescent COVID-19 patients.

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. NAb levels were measured by the SARS-CoV-2 surrogate virus neutralisation test (sVNT). Anonymous clinical and laboratory data were matched with surveillance data for each subject for enabling analyses and applying latent class mixed models for trajectory delineation. Logistic regression models were performed to compare the characteristics between the identified classes. Results: In 2020-2021, 368 convalescent patients in Hong Kong are tested for NAb. Their seroconversion occur within 3 months in 97% symptomatic patients, the level of which are maintained at 97% after 9 months. The NAb trajectories of 200 symptomatic patients are classified by the initial response and subsequent trend into high-persistent and waning classes in latent class mixed models. High-persistent (15.5%) class patients are older and most have chronic illnesses. Waning class patients (84.5%) are largely young adults who are mildly symptomatic including 2 who serorevert after 10 months. Conclusions: Characteristic sub-class variabilities in clinical pattern are noted especially among patients with waning NAb. The heterogeneity of the NAb trajectory patterns and their clinical association can be important for informing vaccination strategy to prevent re-infection.

Surrogate neutralization responses following severe acute respiratory syndrome coronavirus 2 vaccination in people with HIV: comparison between inactivated and mRNA vaccine.

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. METHODS: Adult PWH in care and planning to receive either inactivated (day 0 and day 28) or mRNA-based (day 0 and day 21) vaccine against SARS-CoV-2 were recruited, with blood samples collected over 6 months for surrogate virus neutralization test (sVNT). Demographic and clinical data including age, sex, CD4 + cell count, and suppressed viral load (SVL) status were transcribed for analyses, by simple and multivariable linear regression models, and multivariable linear generalized estimating equations (GEE). RESULTS: A total of 611 HIV patients, 91% male patients, were recruited, of whom 423 and 184 have received mRNA-based and inactivated vaccine, respectively. The seroconversion rate was 99% for mRNA-based vs, 86% for inactivated vaccine [odds ratio (OR) = 21.56, P  = 0.004]. At 6 months, mRNA-based vaccine continued to give a higher response (94 vs. 57%, P  < 0.001). The temporal pattern varied between the two vaccines. By GEE, mRNA-based vaccine ( B  = 40.59, P  < 0.001) and latest SVL status ( B  = 10.76, P  = 0.01) were positively associated with sVNT level, but not latest CD4 + cell count. CONCLUSION: In HIV patients, inactivated vaccine gave a lower peak and shorter duration of sVNT responses compared with mRNA vaccine. The results suggested that different strategies may be needed in boosting the immunity in anticipation of the emergence of variants in the community.

What makes an optimal delivery for PrEP against HIV: A qualitative study in MSM.

BACKGROUND: Pre-exposure prophylaxis (PrEP) is an effective means of HIV prevention for men who have sex with men (MSM), a key population whose engagement is crucial for achieving effective public health outcomes. An optimal service model would be important in planning the implementation of PrEP in places where such service has not been established. METHODS: A qualitative study was conducted to delineate the attributes of an optimal PrEP service model for MSM in Hong Kong, a city where no formal PrEP programs existed. Twenty purposively sampled MSM who were enrollees of two pilot PrEP projects participated in the semi-structured interviews promoting story-telling. The coded data were thematically analyzed following Grounded Theory approach, focusing on uncovering a typology of the essential attributes of an optimal PrEP service model, and the reasons for such preferences. RESULTS: Participating MSM were all ethnic Chinese and aged 26 to 52 years. All had received PrEP from pilot projects in conjunction with periodic screening of sexually transmitted infections (STI), HIV antibody, and plasma creatinine. Four major themes emerged as regards the attributes of a preferred PrEP service: (i) comprehensiveness of HIV/STI and safety monitoring; (ii) convenient unitary service; (iii) stigma-free PrEP access and protecting confidentiality; and (iv) affordable price. Whereas regular provision of PrEP was acceptable to MSM, unaffordability and related stigma were the anticipated challenges for potential service providers. CONCLUSIONS: The qualitative assessment of MSM's preference for PrEP service delivery has yielded important information on the many facets of a desirable service model.

Role of oxidative stress in clofazimine-induced cardiac dysfunction in a zebrafish model.

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.

Failure of pre-exposure prophylaxis with daily tenofovir/emtricitabine and the scenario of delayed HIV seroconversion.

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.

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.

Supramolecular strategy for reducing the cardiotoxicity of bedaquiline without compromising its antimycobacterial efficacy.

Bedaquiline (BDQ) is a newly approved anti-tuberculosis drug in treating multidrug-resistant tuberculosis. However, it has very poor aqueous solubility and several case reports have proposed that BDQ has potential risk of cardiotoxicity to patients. In this present study, we have explored into employing host-guest interactions between a synthetic receptor, cucurbit[7]uril (CB[7]), and BDQ aiming to improve the solubility and reduce the inherent cardiotoxicity of BDQ. HPLC-UV test on the solubility of BDQ in the absence and in the presence of increasing concentrations of CB[7] suggested a host-dependent guest-solubility enhancements. Cardiovascular studies using an in vivo zebrafish model demonstrated that the cardiotoxicity of BDQ was indeed alleviated upon its complexations by the synthetic receptor. Furthermore, our in vitro antibacterial studies suggested that CB[7] formulated BDQ preserved its antimycobacterial efficacy against Mycobacterium smegmatis. Therefore, CB[7] may become a suitable pharmaceutical excipient in formulating BDQ for improving its physiochemical properties (such as solubility), and for alleviating its side effects (such as cardiotoxicity), while the antimycobacterial efficacy of BDQ may be well maintained.

Estimation of the Undiagnosed Intervals of HIV-Infected Individuals by a Modified Back-Calculation Method for Reconstructing the Epidemic Curves.

BACKGROUND: Undiagnosed infections accounted for the hidden proportion of HIV cases that have escaped from public health surveillance. To assess the population risk of HIV transmission, we estimated the undiagnosed interval of each known infection for constructing the HIV incidence curves. METHODS: We used modified back-calculation methods to estimate the seroconversion year for each diagnosed patient attending any one of the 3 HIV specialist clinics in Hong Kong. Three approaches were used, depending on the adequacy of CD4 data: (A) estimating one's pre-treatment CD4 depletion rate in multilevel model;(B) projecting one's seroconversion year by referencing seroconverters' CD4 depletion rate; or (C) projecting from the distribution of estimated undiagnosed intervals in (B). Factors associated with long undiagnosed interval (>2 years) were examined in univariate analyses. Epidemic curves constructed from estimated seroconversion data were evaluated by modes of transmission. RESULTS: Between 1991 and 2010, a total of 3695 adult HIV patients were diagnosed. The undiagnosed intervals were derived from method (A) (28%), (B) (61%) and (C) (11%) respectively. The intervals ranged from 0 to 10 years, and were shortened from 2001. Heterosexual infection, female, Chinese and age >64 at diagnosis were associated with long undiagnosed interval. Overall, the peaks of the new incidence curves were reached 4-6 years ahead of reported diagnoses, while their contours varied by mode of transmission. Characteristically, the epidemic growth of heterosexual male and female declined after 1998 with slight rebound in 2004-2006, but that of MSM continued to rise after 1998. CONCLUSIONS: By determining the time of seroconversion, HIV epidemic curves could be reconstructed from clinical data to better illustrate the trends of new infections. With the increasing coverage of antiretroviral therapy, the undiagnosed interval can add to the measures for assessing HIV transmission risk in the population.

Sexually acquired hepatitis C virus infection: a review.

Sexually acquired hepatitis C virus (HCV) infection remains a public health problem, with significant disease burden primarily in HIV-positive men who have sex with men (MSM). Over the past decades, the epidemic of sexually transmitted HCV infection has continued to expand and the epidemiology of HCV in HIV has changed significantly. In the post-combination antiretroviral therapy era, sexual network characteristics within the specific core group of MSM with increased sexual risk behaviours, including serosorting on the basis of HIV-positive status and intense mucosally traumatic sexual practices, confer increased HCV acquisition and transmission. This review summarizes the current epidemiology of sexually acquired HCV infection and the clinical and immunological contexts of acute HCV infection, and describes the biological, social, and behavioural factors that have facilitated permucosal transmission of HCV in MSM. While the advent of direct-acting antivirals has improved treatment responses significantly, sexually transmitted HCV reinfections occur in a substantial proportion of HIV-positive MSM following clearance of a primary infection. Effective strategies and preventive interventions that are tailored to the MSM communities to facilitate the control of sexually acquired HCV infection cannot be overemphasized.

Community-based sexually transmitted infection screening and increased detection of pharyngeal and urogenital Chlamydia trachomatis and Neisseria gonorrhoeae infections in female sex workers in Hong Kong.

BACKGROUND: Female sex workers (FSWs) are vulnerable to sexually transmitted infections (STIs) and are one of the key populations being infected most by Chlamydia trachomatis and Neisseria gonorrhoeae infections. In Hong Kong, limited data on the burden of chlamydial and gonococcal infections exist because regular screenings are not offered. This study aimed to investigate the prevalence of C. trachomatis and N. gonorrhoeae in FSWs and to assess predictors associated with unprotected fellatio. METHODS: A cross-sectional study was conduct on 340 FSWs attending a community organization for HIV/STI screening, and a questionnaire addressing sociodemographic and behavioral characteristics was administered to all FSWs. RESULTS: The prevalence of syphilis infection was 2.1%, and none was tested positive for HIV. The positivity for pharyngeal C. trachomatis and N. gonorrhoeae was 3.2% and 4.4%, respectively, whereas that for urogenital chlamydial and gonococcal infection was 10.6% and 0.9%, respectively. Of 313 FSWs offering fellatio, having unprotected fellatio with clients was significantly associated with the perceived low risk of contracting STI via fellatio (adjusted odds ratio [OR], 1.88), working in clubs (adjusted OR, 11.14), working on streets (adjusted OR, 3.28), recently started working in the sex industry for 1 year or less (adjusted OR, 3.05), and reporting group sex in the previous year (adjusted OR, 11.03). CONCLUSIONS: The prevalence of HIV and syphilis infection remains low. This study reveals a relatively high prevalence of N. gonorrhoeae detected mostly in the pharynx. Offering pharyngeal screening for STI would facilitate early diagnosis and treatment of gonococcal infection in FSWs in Hong Kong.

Household characteristics and influenza vaccination uptake in the community-dwelling elderly: a cross-sectional study.

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.

Three different patterns of CD4 recovery in a cohort of Chinese HIV patients following antiretroviral therapy - a five-year observational study.

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

Sleep quality in efavirenz-treated Chinese HIV patients - comparing between GT and GG genotype of CYP2B6-516 G/T polymorphisms.

Seventy-two adult Chinese HIV-positive treatment-naïve patients were recruited in a study to evaluate prospectively the associations between CYP2B6 516 G/T polymorphisms and sleep quality following treatment with an efavirenz-based regimen. Overall, the patients gave an allelic frequency of 0.3 for CYP2B6 516 T, and a genotype frequency of 9.4% for TT. Compared to GG, GT gave a higher median value of plasma efavirenz level at four weeks (3.77 mg/L vs 2.59 mg/L, p < 0.001) and 12 months (3.57 mg/L vs 2.97 mg/L, p = 0.026). Using generalised estimating equations analysis to track the variance over time, there was poorer Pittsburgh Sleep Quality Index in GT compared to GG, while GT was associated with a higher efavirenz level of >4 mg/L. There was however no difference in the component sleep scores nor was there direct association between sleep quality and plasma efavirenz levels. The results suggested that CYP2B6 genotype was associated with different patterns of sleep problems, further investigation of which is warranted with the objective of optimizing therapy with efavirenz-based regimens.

The effects of widespread methadone treatment on the molecular epidemiology of hepatitis C virus infection among injection drug users in Hong Kong.

The distribution of HCV genotypes among injection drug users in Hong Kong was assessed in context of methadone treatment availability. Three time periods were defined by the year of initiating injection-on or before 1980, 1981-1994, and 1995-2006-with methadone becoming widely available since the second period. Of the 273 HCV RNA-positive cases, the most prevalent subtype was HCV 6a (52.4%), followed by HCV 1b (38.5%). The new variants of HCV subtypes 6e and 6h were detected. Both subtypes 1b and 6a were prevalent among older injectors, while subtype 3a was more common in young injectors and those initiating injection recently during the third time period. Age (P < 0.05) and recent injection frequency (P < 0.01) were independently associated with HCV 6a infection. Subtype 1b was predominant in the first period, whereas 6a was more common in the second and third. Subtype 1b sequences appeared to have originated at two positions on the phylogenetic tree, while 6a showed a more disperse distribution suggestive of multiple introductions. Phylogenetic analysis on the NS5B region did not reveal specific clustering of any subtype/genotype. Overall, there was no suggestion of outbreaks of HCV. The extensive use of methadone may have protected Hong Kong from the emergence of HCV clusters among injection drug users.

Full genome analysis of an emerging cluster of human immunodeficiency virus type 1 subtype B infection in Hong Kong.

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

A1762T/G1764A mutations of hepatitis B virus, associated with the increased risk of hepatocellular carcinoma, reduce basal core promoter activities.

Hepatitis B virus (HBV) infection is a major global health problem that causes over one million deaths annually. A1762T and G1764A mutations in the basal core promoter are often present in HBV patients but seldom in asymptomatic carriers, and are highly correlated with the increased risk of HBV-associated hepatocellular carcinoma (HCC). In this study, for the first time, we show that the basal core promoter activity of HBV strains isolated from asymptomatic carriers is decreased when 1762A is mutated to 1762T or 1764G is mutated to 1764A by site directed mutagenesis. By contrast, the promoter activity of HBV strains isolated from HCC patients is increased when 1762T and 1764A are reversely mutated into 1762A and 1764G, respectively. 1764G contributes more promoter activity than 1762T. We also show that T1762A and G1764A double mutations synergize the reduction of the promoter activity. A mechanism of HBV evasion from host immunoresponse that may facilitate disease development is also discussed.

Biases in human papillomavirus genotype prevalence assessment associated with commonly used consensus primers.

Consensus primers targeting human papillomaviruses (HPVs) have biases in sensitivity toward certain HPV types. We applied 3 primer sets (GP5+/6+, MY09/11, PGMY09/11) in parallel on 120 Chinese cervical cancer specimens. GP5+/6+ exhibited a poor sensitivity for HPV52, for which the prevalence among squamous cell cervical cancer was underestimated from 14.6% to 0%. The fact that HPV52 should rank second in prevalence among squamous cell cervical carcinoma in Hong Kong could be missed if GP5+/6+, a worldwide commonly used primer set, was selected for HPV detection. Biases in HPV type-specific sensitivity may result in misprioritization of vaccine candidates.

HLA-B alleles, high-risk HPV infection and risk for cervical neoplasia in southern Chinese women.

A population-based study was conducted on 256 southern Chinese with cervical intraepithelial neoplasia grade III (CIN III) or invasive cervical cancer (ICC) and on 258 controls to examine the associations between HLA-B alleles, infection with high-risk human papillomaviruses (HPVs) and the development of cervical neoplasia. HLA-B15 was found to be protective for CIN III/ICC overall (p(corrected) = 0.003), and for HPV52-positive CIN III/ICC (p(corrected) = 0.003). A marginal protective effect of B15 was observed for HPV16-positive CIN III/ICC, but no significant associations were revealed for HPV18- or HPV58-positive cases. None of the HLA-B alleles were found to confer an increased risk for cervical neoplasia. HLA-B15 is common among Asian for whom HPV52, a worldwide uncommon HPV type, also exists in a relatively high prevalence. It would also be worthwhile to assess the association between HLA-B15, HPV52 and cervical cancer in other Asian populations.