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Long COVID has been reported among patients with COVID-19, but little is known about the prevalence and risk factors associated with long COVID 6-12 months after infection with the Omicron variant. This is a large-scale retrospective study. A total of 6242 out of 12 950 nonhospitalized subjects of all ages with SARS-CoV-2 infection (confirmed by polymerase chain reaction/rapid antigen test) during the Omicron dominant outbreak (December 31, 2021-May 6, 2022) in Hong Kong were included. Prevalence of long COVID, frequencies of symptoms, and risk factors were analyzed. Three thousand four hundred and thirty (55.0%) subjects reported at least one long COVID symptom. The most reported symptom was fatigue (1241, 36.2%). Female gender, middle age, obesity, comorbidities, vaccination after infection, having more symptoms, and presenting fatigue/chest tightness/headache/diarrhea in the acute stage of illness were identified as associated risk factors for long COVID. Patients who had received three or more doses of vaccine were not associated with a lower risk of long COVID (adjusted odds ratio 1.105, 95% confidence interval 0.985-1.239, p = 0.088). Among patients with at least three doses of vaccine, there was no significant difference in the risk of long COVID between the CoronaVac vaccine and BNT162b2 vaccine (p > 0.05). Omicron infection can lead to long COVID in a significant proportion of nonhospitalized patients 6-12 months after infection. Further investigation is needed to uncover the mechanisms underlying the development of long COVID and determine the impact of various risk factors such as vaccines., (© 2023 Wiley Periodicals LLC.)

Omicron BA.2.2 is the dominant variant in the Hong Kong outbreak since December 31, 2021. There is no study reporting the weekly symptom profile after infection. In this retrospective study, participants who tested positive for SARS-CoV-2 after December 31, 2021, and registered in the telemedicine system between March 14 and May 6, 2022, were analyzed. Among registered 12 950 self-quarantined COVID-19-positive patients, 11 776 symptomatic patients were included for weekly symptom profile analysis. A total of 4718 (40.1%) patients reported symptoms in the first week after a positive test, 2501 (21.2%) in the second week, 1498 (12.7%) in the third week, 1048 (8.9%) in the fourth week, and 2011 (17.1%) in over 4 weeks. Cough was the most common symptom in all participants. Patients in the first week had higher odds of reporting fever (0.206, 95% confidence interval [CI]: 0.161-0.263, p < 0.001) and sore throat (0.228, 95% CI: 0.208-0.252, p < 0.001). Patients in over 4 weeks had higher odds of reporting fatigue (1.263, 95% CI: 1.139-1.402, p < 0.001). Further, having at least two vaccine doses linked to lower odds of having fever (0.675, 95% CI: 0.562-0.811, p < 0.001), but not associated with the presence of cough and fatigue. Diabetic patients had higher odds of reporting diarrhea (1.637, 95% CI: 1.351-1.982, p < 0.001). Symptoms from Omicron infection may last for more than 4 weeks and symptom profiles vary from week to week. Vaccination and comorbidity affect the symptom profiles., (© 2022 Hong Kong Baptist University. Journal of Medical Virology published by Wiley Periodicals LLC.)

Background: Microdeletions and microduplications can occur in any pregnancy independent of maternal age. The spectrum and features of pathogenic copy number variants including the size, genomic distribution, and mode of inheritance are not well studied. These characteristics have important clinical implications regarding expanding noninvasive prenatal screening for microdeletions and microduplications., Objectives: The aim was to investigate the spectrum and characteristics of pathogenic copy number variants in prenatal genetic diagnosis and to provide recommendations for expanding the scope of noninvasive prenatal screening for microdeletions and microduplications., Study Design: This was a retrospective study of 1510 pregnant women who underwent invasive prenatal diagnostic testing by chromosomal microarray analysis. Prenatal samples were retrieved by amniocentesis or chorionic villus sampling and sent to our prenatal genetic diagnosis laboratory for chromosomal microarray analysis. The risk of carrying a fetus with pathogenic copy number variants is stratified by the patients' primary indication for invasive testing. We searched the literature for published prenatal chromosomal microarray data to generate a large cohort of 23,865 fetuses. The characteristics and spectrum of pathogenic copy number variants including the type of aberrations (gains or losses), genomic loci, sizes, and the mode of inheritance were studied., Results: Overall, 375 of 23,865 fetuses (1.6%) carried pathogenic copy number variants for any indication for invasive testing, and 44 of them (11.7%) involve 2 or more pathogenic copy number variants. A total of 428 pathogenic copy number variants were detected in these fetuses, of which 280 were deletions and 148 were duplications. Three hundred sixty (84.1%) were less than 5 Mb in size and 68 (15.9%) were between 5 and 10 Mb. The incidence of carrying a pathogenic copy number variant in the high-risk group is 1 in 36 and the low-risk group is 1 in 125. Parental inheritance study results were available for 311 pathogenic copy number variants, 71 (22.8%) were maternally inherited, 36 (11.6%) were paternally inherited, and 204 (65.6%) occurred de novo., Conclusion: Collectively, pathogenic copy number variants are common in pregnancies. High-risk pregnancies should be offered invasive testing with chromosomal microarray analysis for the most comprehensive investigation. Detection limits on size, parental inheritance, and genomic distribution should be carefully considered before implementing copy number variant screening in expanded noninvasive prenatal screening., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: In Hong Kong, with an increasing number of children experiencing mental health issues, there is a need to not only develop innovative interventions but also develop comprehensive prevention interventions so as to reduce their anxiety symptoms and enhance their emotional management and interpersonal relationships., Objective: The aim of this study was to determine the effectiveness of The Adventures of DoReMiFa, an integration model of the cognitive-behavioral approach and positive psychology by using digital game-based and school-based mental health enhancement intervention to magnify the social and emotional health and well-being of the school children in Hong Kong aged 9 to 11 years., Methods: A quasi-experimental design method was used to evaluate this digital game and school-based intervention. The Adventures of DoReMiFa was piloted in 4 primary schools where students were allocated to either an intervention or a control group. The participants were assessed at pre- and postintervention with a 6-month follow-up measuring their mental health knowledge, levels of anxiety symptoms, positive and negative thinking, perspective-taking, and self-esteem., Results: A total of 459 primary school students from 4 primary schools participated in the study. The response rate on the questionnaires answered on the Web was up to 85.1% (391/459). Compared with the control group, the intervention group was found to have significant association with improved mental health knowledge at the time immediately after the intervention (beta=.46; P=.01) and in the 6-month postintervention period (beta=.66; P<.001); for perspective-taking, the intervention group had exhibited a significant improvement 6 months after the completion of the universal program (beta=1.50; P=.03). The intervention, however, was found not to be effective in reducing the rates of anxiety symptoms and negative thinking among the participating students., Conclusions: The Adventures of DoReMiFa, an integration of a digital game-based and school-based mental health enhancement intervention, was shown to be effective in elevating the knowledge of mental health and promoting perspective-taking in the primary school students of Hong Kong. Although there was insufficient evidence to support a reduction in symptoms of anxiety and negative automatic thoughts, the overall results were still encouraging in that a preventive effect was found, indicating that the program has the potential to enhance the mental well-being of schoolchildren. It also suggests that knowledge enhancement may not necessarily lead to behavior change, and more focused effort may be needed to achieve the translation. The implications and limitations of this study and suggestions for future research were also discussed., (©Angie KY Shum, Eliza SY Lai, Wing Gi Leung, Mabel NS Cheng, Ho Kit Wong, Sam WK So, Yik Wa Law, Paul SF Yip. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 05.04.2019.)

Background: Older adults usually have a higher suicide rate than the general population. There are helpline services provided to older adults but limited studies have examined the suicidal risks among the users, and how those services could be used as a platform to engage older adults in suicide prevention., Methods: In regard to elderly suicide prevention, this study explored the potential usefulness and relevance of a telephone helpline service in Hong Kong, which had 106,583 users during 2012-2015. An estimation on the suicide rates of the users was made and compared with the general older adult population in Hong Kong. The users' suicide risks and their associated factors were assessed by survival analyses and an estimation system on the users' suicide mortality likelihood was also tested., Results: The suicide rates of both male and female users were more than two times higher than the general older adult population in Hong Kong. The users' risks of suicides were greater at the early period of using the service; men, living alone, and having a history of mental illnesses were also associated with increased risks. Based on the identified factors, an estimation system was developed with a sensitivity of 0.73 and specificity of 0.54., Limitations: A secondary data analysis., Conclusions: By identifying a suicide risk profile and distinct telephone calling pattern among the users, early detection and a warning system should be implemented to allow timely intervention to reduce the number of older adult suicides in the community., (Copyright © 2018 Elsevier B.V. All rights reserved.)

While hepatitis C virus (HCV) infection is long known to be associated with parenteral exposure, the specific route of transmission is not identified in a proportion of infected patients. Taking blood donors as the surrogate of healthy adults in the community in Hong Kong, we identified 91 HCV-infected donors (≤0.02% positive rate) in 2014-2016, of whom 46 were recruited in a mixed-method study to examine their transmission routes. A majority (75%) of the recruited donors were HCV RNA positive, with the predominant subtypes being 1b and 6a. From the results of the structured self-administered questionnaire and in-depth interviews, only 14 (30%) recruited donors could be traced to past history of contaminated blood transfusion (n = 9) or injection drug use (n = 5). Case-control analyses with 3 different control groups were performed to examine factors associated with HCV infection in multivariable analyses. High-risk sexual behaviour, body piercing, intramuscular injection and vaccine inoculation abroad, having lived abroad for >3 months were significantly associated with HCV in donors with otherwise nonidentifiable source of infection. While the specific route of transmission cannot be established for each person, associations with multiple parenteral exposures outside Hong Kong were observed. The World Health Organization has advocated for the global elimination of HCV by 2030. With a high proportion of HCV-infected persons who are unaware of their infections, HCV elimination could be hard to achieve., (© 2017 John Wiley & Sons Ltd.)

Objective: Elevated plasma adrenomedullin (ADM) levels are associated with cardiovascular diseases. Single nucleotide polymorphisms (SNPs) in the gene encoding ADM (ADM) are associated with plasma ADM levels. The presence of a nuclear factor for interleukin-6 (IL-6) expression binding site in the promoter region of the ADM gene suggests a possible relationship between the expression of the ADM and IL-6. Therefore, we investigated whether plasma ADM levels are related to SNPs in the gene encoding IL-6 (IL6)., Methods: Plasma ADM levels were measured in 476 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS2). The subjects were genotyped for three tagging SNPs in the IL6 gene., Results: The minor allele frequencies of the IL6 SNPs rs17147230, rs1800796 and rs2069837 were 41·8%, 20·0% and 15·4%, respectively. The tagging SNP, rs17147230, was associated with plasma ADM levels after adjusting for age and sex (β=-0·096, P = 0·034). The association was significant in women (β=-0·115, P = 0·021) but not in men. Among all subjects, plasma ADM levels decreased with an increasing number of minor alleles of rs17147230 in multivariate analysis (P = 0·034). Compared to subjects with the AA genotype, subjects with the TT genotype had plasma ADM levels 12·8% lower (95% CI: 0·6-23·5%, P = 0·041). Haplotype analysis demonstrated a significant association of the haplotype ACA with plasma ADM levels in women (P < 0·05)., Conclusion: Plasma ADM levels are related to the SNP rs17147230 in IL6 gene. The effect of the polymorphism on inflammation and cardiovascular disease remains to be determined., (© 2012 John Wiley & Sons Ltd.)

Background: Predonation hemoglobin (PDH) is used to safeguard donors' welfare, and low hemoglobin (Hb) is known to be the most frequent reason for donor deferral. A study was initiated to assess the PDH and iron status of blood donors in Hong Kong., Study Design and Methods: This observational study was designed with four groups of whole blood donors invited (group 1-eligible first time donors, group 2-eligible repeat donors with zero or one donation in preceding 12 months, group 3-eligible repeat donors with at least two donations in preceding 12 months, group 4-repeat donors being deferred for low PDH). Predonation blood samples were obtained for blood counts and iron status. Mann-Whitney test, Kruskal-Wallis test, and chi-square test for trend were applied for statistical analysis., Results: A total of 836 donors were recruited, of which 35 were excluded because of hemoglobinopathy. An inverse relationship between serum ferritin level and number of donations in the preceding 12 months was observed in both sexes. Iron deficiency was significantly seen in 35.1% of male and 65.3% of female deferred donors. More importantly, up to 7.2, 5.8, and 29.5% of the female donors in groups 1, 2, and 3 were found to be iron deficient despite having a high enough PDH., Conclusion: This is the first study to assess PDH and iron status in Chinese blood donors. Iron depletion is noted with increasing number of blood donations in the preceding 12 months. Advice on iron repletion is a necessary step for donor welfare and strategies should be developed to ensure that donors have adequate PDH., (© 2012 American Association of Blood Banks.)

Background: Hepatitis C virus (HCV) infection can result in serious hepatic complications and hence potentially significant burden to the society. Despite advances in technology, transfusion-transmitted HCV infection still exists. To further minimise the risk, a review on the epidemiology of HCV infection among Chinese blood donors in Hong Kong was conducted., Methods: All donations associated with HCV infection confirmed by positive serologic diagnosis with or without molecular confirmation during the period from 2003 to 2010 were studied. Demographic data were retrieved and risk factors were identified., Results: HCV infection was more commonly seen in first time donors and donors with blood transfusion history before the availability of HCV testing, whereas its association with intravenous drug use was noted to be decreasing. Interestingly, half of the HCV positive donors in 2008-2010 were young donors aged below 21, which was also the group with the highest rate of no known source of infection., Conclusion: A subgroup of younger age donors was found to have no known risk factor. To develop better screening strategy, it is recommended that a more detailed analysis of this group of donors is required., (© 2011 The Authors. Transfusion Medicine © 2011 British Blood Transfusion Society.)

Background: Eating disorders are affecting an increasing number of high school students in Western and Asian countries. The availability of an effective screening tool is crucial for early detection and prompt intervention., Objective: The objective of this study was to examine the validity and reliability of the SCOFF questionnaire for screening eating disorders in Hong Kong high school students., Design: This study adopted a cross-sectional design to examine the psychometric properties of the SCOFF questionnaire., Participants: A panel of 7 experts and 936 students of a high school participated in the study., Method: The SCOFF questionnaire was translated into Chinese and back-translated into English to ensure the linguistic equivalence. A panel of 7 experts involved in the content validation of the SCOFF questionnaire. The Eating Disorder Examination-Questionnaire (EDE-Q) was used as the "reference standard" to assess its concurrent validity in 936 students of a high school. Its reliability was examined by internal consistency and the test-retest method at a 2-week interval and with 38 students., Results: The SCOFF questionnaire achieved an agreement of 86-100% among the experts for the content relevance. Of 812 students (86.8%) who responded to this study, their SCOFF scores correlated significantly with their global scores on the EDE-Q (r=0.5, P<0.01). Students identified as potentially having eating disorders had significantly higher scores in the EDE-Q than those not identified as such by SCOFF. The SCOFF questionnaire demonstrated moderate test-retest reliability (ICC=0.66) and an acceptable internal consistency reliability (Cronbach's alpha=0.44-0.57) in comparing with previous studies., Conclusion: The SCOFF questionnaire has acceptable psychometric properties in the Chinese culture. It will be useful for detecting potential eating disorders and assisting health promotion activity.

Poor human-to-human transmission of influenza A H5N1 virus has been attributed to the paucity of putative sialic acid alpha2-3 virus receptors in the epithelium of the human upper respiratory tract, and thus to the presumed inability of the virus to replicate efficiently at this site. We now demonstrate that ex vivo cultures of human nasopharyngeal, adenoid and tonsillar tissues can be infected with H5N1 viruses in spite of an apparent lack of these receptors.

Outbreaks of H5N1 highly pathogenic avian influenza (HPAI) that occurred in Hong Kong up until February/March 2002 were controlled by stamping out. With endemic presence of the virus in the region and large daily importation of poultry to Hong Kong, the Administration considered that further risk management measures, in addition to improved biosecurity and enhanced surveillance, were necessary to prevent outbreaks. Vaccination using a killed H5N2 vaccine was evaluated over a 12-month period in the district with the last HPAI cases in the early 2002 outbreak. The vaccination trial showed that farmer-administered killed H5N2 vaccine produced suitable flock antibody responses; vaccinated birds were protected against H5N1 HPAI virus challenge and excreted significantly less H5N1 virus; and vaccination was able to control virus excretion in flocks during field outbreaks. Universal vaccination of local chicken farms was introduced in June 2003 and by the end of 2003 all chickens entering the live poultry markets in Hong Kong were vaccinated by killed H5N2 vaccine. In addition to vaccination, an enhanced biosecurity programme on farms and in live poultry markets and a comprehensive surveillance programme in poultry, wild birds, recreation park birds and pet birds were in place. Vaccination use and performance is closely monitored. This programme was successful in protecting local farms and live poultry markets from H5N1 outbreaks during the regional H5N1 outbreaks in 2004.