Diabetes induces a substantial global burden of disease. The World Health Organization reported that the number of people with diabetes increased from 108 million in 1980 to 422 million in 2014, and the global prevalence of diabetes escalated from 4.7% in 1980 to 8.5% in 2014.1 The mortality rate due to complications of diabetes has been predicted to double between 2005 and 2030.1 It has been estimated that almost half of all patients with diabetes (49.7%) remain undiagnosed and unaware of their conditions.2 The American Diabetes Association recommends that people aged ≥45 years should be screened for diabetes or prediabetes, especially individuals who are overweight or obese.3 Patients with risk factors of diabetes should receive screening at an earlier age or at more frequent intervals. Laboratory-based criteria for diagnosing diabetes and prediabetes include fasting plasma glucose (FPG) level, glycated haemoglobin (HbA1c) level, and 75-g Oral Glucose Tolerance Test.3 In asymptomatic individuals, two abnormal glycaemic results are required to establish a diagnosis of diabetes.3 The United States Preventive Services Task Force recently updated recommendations and proposed screening from age 40 to 70 years at 3-year intervals, with all three tests being suitable as screening modalities.4 The Hong Kong Reference Framework for Diabetes Care for Adults in Primary Care Settings5 of the Primary Healthcare Office, the Hong Kong Government recommends that screening should begin at age 45 years, and should be conducted every 1 to 3 years, based on the presence of diabetes risk factors.5 Other authorities such as the Canadian Task Force on Preventive Health Care6 recommend screening based on HbA1c levels in high-risk individuals only, and those at low to moderate risk should complete a validated risk calculator such as FINDRISC7 or CANRISK8 to determine subsequent screening arrangements. Early diagnosis and proper treatment of type 2 diabetes mellitus reduces cardiovascular morbidity and mortality.9 Early detection also enables quality care to slow disease progression, prevent complications, and reduce the hospital care burden and healthcare costs.

In this issue of the Hong Kong Medical Journal, Chan and colleagues10 retrospectively studied 1566 patients who underwent total knee arthroplasties (TKAs) at an institution where universal diabetes screening was implemented. Among them, 46.6% received HbA1c screening during preoperative assessment of TKAs 2 to 3 months before the scheduled operation, and all patients with HbA1c level ≥7.5% were referred to an endocrinologist for optimisation of glycaemic control before the scheduled TKA. The other 53.4% who did not receive HbA1c screening acted as historical controls. The authors found that up to 38% of patients had undiagnosed prediabetes or diabetes as identified by the universal HbA1c screening programme. In addition, the incidence of prosthetic joint infections after surgery was significantly lower in patients who received HbA1c screening than in those who did not (0.2% vs 1.0%, P=0.027). These findings suggest that universal HbA1c screening seems justifiable for all patients before they undergo TKA. Although only 17 patients were referred to an endocrinologist, the lower rate of prosthetic joint infections among patients who had HbA1c screening may be attributed to the more meticulous perioperative care for those identified as having dysglycaemia. Whether HbA1c screening of dysglycaemia directly led to the lower rate of prosthetic joint infections remains uncertain, since the infection rate in the cohort before universal screening was introduced in March 2017 was similar for patients with diabetes or prediabetes and those without diabetes. The yield of screen-detected diabetes mellitus since 2017 was also low in this study, with most having prediabetes, most of whom were not referred to an endocrinologist for treatment. The major limitations of the study include its retrospective nature, single-centre design, lack of randomisation between groups, and the possibility of missing variables which could be confounders. Nevertheless, the findings contribute to a solid foundation where future prospective studies may offer more definitive practice-changing recommendations for clinical guidelines. Because diabetes is a silent condition and many people with diabetes remain undiagnosed, increased clinical awareness of the condition with screening using HbA1c level, particularly before major operations such as TKA, appears to be a justifiable approach.

Universal diabetes screening in the general population may also be worthwhile. However, several issues must be considered before formal implementation of population-based screening programmes. First, a systematic review and meta-analysis including 49 studies of screening tests and 50 intervention trials showed that HbA1c level has only average sensitivity of 0.49 (95% confidence interval [95% CI]=0.40-0.58) and specificity of 0.79 (95% CI=0.73-0.84),11 whereas FPG level is specific (0.94, 95% CI=0.92-0.96) but not sensitive (0.25, 95% CI=0.19-0.32). The diagnostic accuracy of HbA1c level for diabetes has also been challenged—in a cohort of 5764 adult patients without diagnosed diabetes, the sensitivity of HbA1c ≥6.5% was only 43.3% and 28.1% when FPG and 2-hour plasma glucose, respectively, were used as criteria.12 Although HbA1c level has advantages of greater convenience (not requiring fasting) and fewer day-to-day variations, HbA1c level may be affected by assay interference due to haemoglobinopathies and conditions altering red blood cell turnover such as recent blood loss. Second, diabetes screening fulfils the Wilson and Jungner criteria,13 but one of the most important determinants of programme success includes screening uptake and persistent adherence over time. Although a variety of cancer screening programmes, such as for colorectal and cervical cancer, have been implemented to the local population to address the rapidly rising burden on Hong Kong’s healthcare system, the uptake rate remains suboptimal. Conversely, few programmes have specifically targeted metabolic diseases such as diabetes. The Hong Kong Government’s effort to enhance the provision of primary care and encourage the uptake of preventive care among the elderly people through the Elderly Health Care Voucher Scheme was launched on 1 January 2009, and was regularised into a recurrent programme in 2014. Eligible residents aged ≥65 years are entitled to an annual voucher of HK$2000 to utilise private sector primary care preventive services. However, it has been shown that a majority of elderly people in Hong Kong thought the Scheme would encourage them to utilise acute services rather than preventive care or chronic disease management in the private sector.14

Before a universal diabetes screening programme for the general public can be successful, the perceptions of, attitudes to, enablers of, and barriers to diabetes screening should be explored among various stakeholders, including prospective programme participants, physicians practising in various sectors, and policy makers. These will identify pertinent variables that could enhance screening participation and programme design. Furthermore, the cost-effectiveness of screening using different test modalities starting at different age-groups should be evaluated. More work is needed, as effective community-based interventions are required to enhance screening uptake and improve the impact of diabetes screening through further evaluations to inform policy formulation and implementation.

All authors contributed to the editorial, approved the final version for publication, and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

1. World Health Organization. Diabetes fact sheet. 2020. Available from: http://www.who.int/mediacentre/factsheets/fs312/en/. Accessed 12 Jul 2020.

2. Cho NH, Shaw JE, Karuranga S, et al. IDF Diabetes Atlas: Global estimates of diabetes prevalence for 2017 and projections for 2045. Diabetes Res Clin Pract 2018;138:271- 81. Crossref

3. American Diabetes Association. 2. Classification and diagnosis of diabetes: standards of medical care in diabetes—2020. Diabetes Care 2020;43(Suppl 1):S14-31. Crossref

4. Siu AL, US Preventive Services Task Force. Screening for abnormal blood glucose and type 2 diabetes mellitus: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2015;163:861-8. Crossref

5. Primary Healthcare Office. Food and Health Bureau, Hong Kong SAR Government. Hong Kong Reference Framework for Diabetes Care for Adults in Primary Care Settings. Available from: https://www.fhb.gov.hk/pho/english/health_professionals/professionals_diabetes_pdf.html. Accessed 12 Jul 2020.

6. Pottie K, Jaramillo A, Lewin G, et al. Recommendations on screening for type 2 diabetes in adults. CMAJ 2012;184:1687-96. Correction in: CMAJ 2012;184:1815. Crossref

7. Makrilakis K, Liatis S, Grammatikou S, et al. Validation of the Finnish diabetes risk score (FINDRISC) questionnaire for screening for undiagnosed type 2 diabetes, dysglycaemia and the metabolic syndrome in Greece. Diabetes Metab 2011;37:144-51. Crossref

8. Robinson CA, Agarwal G, Nerenberg K. Validating the CANRISK prognostic model for assessing diabetes risk in Canada’s multi-ethnic population. Chronic Dis Inj Can 2011;32:19-31.

9. Herman WH, Ye W, Griffin SJ, et al. Early detection and treatment of type 2 diabetes reduce cardiovascular morbidity and mortality: a simulation of the results of the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen-Detected Diabetes in Primary Care (ADDITION-Europe). Diabetes Care 2015;38:1449-55. Crossref

10. Chan VW, Chan PK, Woo YC, et al. Universal haemoglobin A1c screening reveals high prevalence of dysglycaemia in patients undergoing total knee arthroplasty. Hong Kong Med J 2020;26:304-10. Crossref

11. Barry E, Roberts S, Oke J, Vijayaraghavan S, Normansell R, Greenhalgh T. Efficacy and effectiveness of screen and treat policies in prevention of type 2 diabetes: systematic review and meta-analysis of screening tests and interventions. BMJ 2017;356:i6538. Crossref

12. Karnchanasorn R, Huang J, Ou HY, et al. Comparison of the current diagnostic criterion of HbA1c with fasting and 2-hour plasma glucose concentration. J Diabetes Res 2016;2016:6195494. Crossref

13. Wilson JM, Jungner YG, Organization WH. Principles and practice of mass screening for disease [in Spanish]. Bol Oficina Sanit Panam 1968;65:281-393.

14. Yam CH, Wong EL, Fung VL, Griffiths SM, Yeoh EK. What is the long term impact of voucher scheme on primary care? Findings from a repeated cross sectional study using propensity score matching. BMC Health Serv Res 2019;19:875. Crossref

Social media refers to internet-based tools that enable individuals and organisations to communicate and share ideas, personal messages, and images. Social media also provides a platform for collaboration among researchers and other like-minded individuals.1 These social networking activities have offered our community access to a very rich body of medical knowledge, in order to build both interpersonal and professional relationships. The global utilisation of social media has increased from 7% in 2005 to 65% in 2015,2 and has increasingly played a crucial role for the academic community to promote research, establish academic networks, and interact with the general public online. Many journals have now started to harness the influential capabilities of social media to share their articles to potential readers.3 Altmetrics, another metric of evaluating research impact, considers engagement of social media in computing impact.4 5

Is there evidence that social media works? In this digital era, the advancement in technology has allowed rapid communications without geographical restrictions. The use of social media and hashtags have been a norm for academics to have rapid exchange of information during medical conferences. It is not uncommon to have a ‘viral effect’ in the dissemination of medical information, where the degree of interaction and engagement among participants can be very overwhelming.6 Hawkins et al7 have analysed the impact of Twitter “tweet chat” sessions by evaluating the Twitter activity metadata tagged with the #JACR hashtag from tweet chat sessions promoted by the Journal of American College of Radiology. They found that the average monthly journal website visits and page views directly from Twitter increased 321% and 318%, respectively. In addition, the authors found that organising Twitter microblogging activities around disciplines of general interest to their target audience could potentially increase the reach and number of readers for medical journals. There is also evidence that citations to an article may be heavily reliant on visible exposure of the academic output.8 It has been argued that composing a high-quality article in journals could only confer 50% of the chance of being cited, whilst the other half rested on broad promotion and dissemination of the published articles.9 10 11 The objectives of employing social media for medical journals include enhancing their reach, timeliness, and efficiency of sharing medical literature. These objectives are shared by the Hong Kong Medical Journal (HKMJ), as pledged at the Journal’s inception in 1995 to provide “a useful source of medical information on advances in medical research and clinical practice”12 in a timely and efficient manner, and reiterated in February 2017.13

It is important that articles published in HKMJ reached and benefit as many readers as possible. Among the 10 most frequently cited HKMJ articles in the past years, seven were published in the Review Article or Medical Practice sections14 15 16 17 18 19 20; these papers likely represent more practice-changing content, and deserve to be disseminated to as wide an audience as possible. In order to expand the audience of HKMJ, from 1 June 2020 onwards, the Journal will formally launch a social media presence, overseen by the “HKMJ Expert Advisory Panel on Social Media”. Professor Jeremy Yuen-chun Teoh, an Editor of the HKMJ, has agreed to act as Panel Chair. We are also pleased and grateful that Dr Regina Sit, our Editor, and the three newest members of our Editorial Board, Dr Jason Yam, Dr Sherry Chan, and Dr Jason Cheung have also agreed to join the panel. These three individuals were awardees of the 2019 Best Original Research by Young Fellows, organised by the Hong Kong Academy of Medicine Foundation.

There are at least three social media platforms that we will leverage, including Facebook, Twitter, and LinkedIn, with each bringing different benefits: Facebook is currently the most widely used social media platform in Hong Kong21; Twitter allows fast and efficient communication with academics globally22 23; and LinkedIn is more widely used internationally for building professional networks of colleagues and collaborators. We believe these platforms will allow us to reach our targeted audience in an effective manner. In order to enhance readership, we will also start presenting key results of newly published studies in the form of visual abstracts; this has been shown to be very useful in enhancing engagement with healthcare professionals.24 This panel is also charged to ensure maintenance of patient confidentiality, provision of accurate interpretation of research findings, and ethical use of social media based on the guidelines published by professional organisations such as the American Medical Association.25 It is also an obligation to safeguard the quality of information being disseminated and to ensure professional and appropriate use of the social media platforms. We hope our readers will appreciate and utilise these initiatives, and share their thoughts and experience with us, by joining us on social media, or emailing the Editorial Office at hkmj@hkmj.org.hk.

1. Ventola CL. Social media and health care professionals: benefits, risks, and best practices. P T 2014;39:491-520.

2. Enago Academy. How social media promotion increase research citation? Available from: https://www.enago.com/academy/how-social-media-promotion-increase-research-citation/. Accessed 10 May 2020.

3. Lopez M, Chan TM, Thoma B, Arora VM, Trueger NS. The social media editor at medical journals: responsibilities, goals, barriers, and facilitators. Acad Med 2019;94:701-7. Crossref

4. Cann A, Dimitriou K, Hooley T. Social media: a guide for researchers. February 2011. Available from: https://www.researchgate.net/publication/261990960_Social_Media_A_Guide_for_Researchers. Accessed 10 May 2020.

5. Harris S. Making research connections with social media: advice for researchers. 25 March 2015. Available from: https://www.authoraid.info/en/resources/details/1240/. Accessed 10 May 2020.

6. Teoh JY, Mackenzie G, Smith M, et al. Understanding the composition of a successful tweet in urology. Eur Urol Focus 2020;6:450-7. Crossref

7. Hawkins CM, Hillman BJ, Carlos RC, Rawson JV, Haines R, Duszak R Jr. The impact of social media on readership of a peer-reviewed medical journal. J Am Coll Radiol 2014;11:1038-43. Crossref

8. Marashi SA, Hosseini-Nami SM, Alishah K, et al. Impact of Wikipedia on citation trends. EXCLI J 2013;12:15-9.

9. Ebrahim NA. Publication marketing tools “Enhancing Research Visibility and Improving Citations”. October 2012. Available from: https://www.researchgate.net/publication/232045669_Publication_Marketing_Tools_-_Enhancing_Research_Visibility_and_Improving_Citations. Accessed 10 May 2020.

10. Bong Y, Ebrahim NA. Increasing visibility and enhancing impact of research. Asia Research News 30 Apr 2017. Available from: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2959952. Accessed 10 May 2020.

11. Fagbule OF. Use of social media to enhance the impact of published papers. Ann Ib Postgrad Med 2018;16:1-2.

12. Lee JC, Yu YL. Inaugural editorial. Hong Kong Med J 1995;1:4.

13. Wong MC. Exerting an impact on clinical practice—upholding quality, visibility, and timeliness of publications. Hong Kong Med J 2017;23:4-5. Crossref

14. Leung AK, Hon KL, Leong KF, Sergi CM. Measles: a disease often forgotten but not gone. Hong Kong Med J 2018;24:512-20. Crossref

15. Kan HS, Chan PK, Chiu KY, et al. Non-surgical treatment of knee osteoarthritis. Hong Kong Med J 2019;25:127-33. Crossref

16. Hong YL, Yee CH, Tam YH, Wong JH, Lai PT, Ng CF. Management of complications of ketamine abuse: 10 years’ experience in Hong Kong. Hong Kong Med J 2018;24:175-81. Crossref

17. Tsang AC, Yeung RW, Tse MM, Lee R, Lui WM. Emergency thrombectomy for acute ischaemic stroke: current evidence, international guidelines, and local clinical practice. Hong Kong Med J 2018;24:73-80. Crossref

18. Wong PC, Chan YC, Law Y, Cheng SW. Percutaneous mechanical thrombectomy in the treatment of acute iliofemoral deep vein thrombosis: a systematic review. Hong Kong Med J 2019;25:48-57. Crossref

19. Yee A, Tsui NB, Chang YN, et al. Alzheimer’s disease: insights for risk evaluation and prevention in the Chinese population and the need for a comprehensive programme in Hong Kong/China. Hong Kong Med J 2018;24:492-500. Crossref

20. Chiu PK, Lee AW, See TY, Chan FH. Outcomes of a pharmacist-led medication review programme for hospitalised elderly patients. Hong Kong Med J 2018;24:98-106. Crossref

21. Penetration rate of leading social networks in Hong Kong as of 3rd quarter of 2019. Available from: https:// www.statista.com/statistics/412500/hk-social-network-penetration/. Accessed 10 May 2020.

22. Mohammadi E, Thelwall M, Kwasny M, Holmes KL. Academic information on Twitter: A user survey. PLoS One 2018;13:e0197265. Crossref

23. Gudaru K, Blanco LT, Castellani D, et al. Connecting the urological community: The #UroSoMe experience. J Endoluminal Endourol 2019;2:e20-9. Crossref

24. Chapman SJ, Grossman RC, FitzPatrick ME, Brady RR. Randomized controlled trial of plain English and visual abstracts for disseminating surgical research via social media. Br J Surg 2019:1611-6. Crossref

25. Shore R, Halsey J, Shah K, et al. Report of the AMA Council on Ethical and Judicial Affairs: Professionalism in the use of social media. J Clin Ethics 2011;22:165-72.

The 2019 coronavirus disease (COVID-19) is caused by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2).1 The COVID-19 is primarily an acute viral respiratory disease which can manifest as acute upper or lower respiratory tract syndrome of varying severity, from asymptomatic virus shedding, rhinorrhoea, sore throat, conjunctivitis to cough, asymptomatic or silent hypoxia, chest discomfort, respiratory failure, or even multiorgan failure.1 2 Extrapulmonary manifestations include diarrhoea, lymphopenia, thrombocytopenia, deranged liver and renal function, rhabdomyolysis, anosmia, dysgeusia, meningoencephalitis, Guillain-Barre syndrome, Kawasaki disease like multisystem vasculitis, and thromboembolism.3 4 5 6 7 8 9 The outcome of COVID-19 is largely affected by older age and the presence of obesity and other underlying co-morbidities.10 11 The crude fatality varies widely for different geographical regions from 0.4% to 10%.12 13

Despite over 6 million COVID-19 cases and 360 000 deaths globally, Hong Kong has a total of about 1094 cases at the time of writing, which is one of the lowest per million population among developed regions. The painful experience of the SARS outbreak in 2003 sparked a large body of local animal surveillance, which showed that 39% of Chinese horseshoe bats could be harbouring bat SARS-related coronaviruses.14 Knowing that coronaviruses are prone to genetic mutations and recombination which produce new virus species, and the presence of a large reservoir of SARS-related coronaviruses in these horseshoe bats, together with the culture of eating exotic mammals in southern China, Hong Kong has anticipated and prepared for the re-emergence of SARS and other novel viruses from animals since 2007.15

Based on soft intelligence that an epidemic due to a suspected SARS-related coronavirus was looming in Wuhan on 31 December 2019, border thermal scanning and consensus reverse transcription polymerase chain reaction (RT-PCR) assays for unexplained pneumonia were started. The serious response level was activated by Centre for Health Protection on 4 January 2020. The University of Hong Kong–Shenzhen hospital has served as the sentinel for Hong Kong by identifying the first family cluster of COVID-19 who presented with symptoms after returning from Wuhan on 10 January 2020.1 This family cluster allowed us to preliminarily validate our in-house test for SARS-CoV-2 before commercial test kits were available. This family cluster showed that COVID-19 can be acquired from hospital, spreads very efficiently in the family setting with six out of seven members affected, and can have mild or asymptomatic manifestations.

Hong Kong is at high risk for COVID-19 dissemination. It is among the most densely populated regions globally with at least 200 000 people living in subdivided flats of 60 square feet or less. Furthermore, Hong Kong has a large elderly population with 1.27 million people over the age of 65 years who are susceptible to severe COVID-19. Hong Kong is also at high risk of travel-related case importation, as there are about 150 000 people crossing the Shenzhen–Hong Kong border and about 200 000 travelling via Hong Kong International Airport daily. Finally, Hong Kong has a cool dry winter which may favour virus transmission and its environmental stability. In view of the high number of mild or asymptomatic cases, the Hong Kong public was advised by medical colleagues from different medical specialties to practice universal masking in addition to good hand hygiene on 24 January 2020, despite some local dissenting views and opposite recommendation by the World Health Organization and overseas health authorities. The compliance of our community with face mask went up to 97% during the morning rush hour.16 It turned out that only 40% of our COVID-19 patients were locally acquired cases, and most local clusters of transmissions were related to mask-off activities. Thus, universal or community-wide masking, in addition to the standard border controls, case finding by extensive testing, mandatory admission for cases, rapid contact tracing and quarantine, and social distancing measures, may have given Hong Kong an edge in controlling the local spread of COVID-19. The high professional standard of Hong Kong healthcare workers, the excellent training in infection control, and the adequate supply of personal protective equipment have resulted in zero COVID-19–related mortality and morbidity among our hospital personnel 5 months after the pandemic began.

Epidemiological decisions must be made early enough to be effective, as transmission may have occurred 14 days before the case is detected. Thus, the first case from mainland China should immediately lead to land border control and quarantine of returnees. The first overseas case should lead to testing at the airport and quarantine of all overseas returnees. Increasing numbers of local clusters of untraceable sources should mandate more social distancing. But early case detection depends on extensive testing by RT-PCR especially for patients with mild symptoms. Extensive RT-PCR screening will continue to be one of the most important indicators guiding epidemiological decisions.

However, taking clinical specimens for RT-PCR by nasopharyngeal and throat swabbing of asymptomatic individuals induces discomfort and occasionally nasal bleeding. It may also induce coughing and sneezing, which endangers the healthcare workers. Mass screening would lead to a shortage of swabs. Hong Kong has circumvented these difficulties by patient self-collection of early morning posterior oropharyngeal (deep throat) saliva before breakfast and mouth rinsing.3 17 During sleep, the nasopharyngeal secretions of the upper respiratory tract will go posteriorly and pool around the oropharynx together with the bronchopulmonary secretions of the lower respiratory tract moved up by ciliary activity to almost the same level. Both upper and lower respiratory tract secretions are important for laboratory diagnosis because many patients have peripheral multifocal ground glass opacities on their lung computed tomography scan despite paucity of respiratory symptoms. If the patient can clear the throat by a coughing and gurgling manoeuvre at least 5 to 10 times into a sputum container with 2 mL of viral transport medium, the sensitivity would be similar if not better than the nasopharyngeal and throat swab. This is especially useful for daily viral load monitoring in antiviral treatment trial during which many patients resent the discomfort of taking daily nasopharyngeal swabs.18 With reliable collection of early morning posterior oropharyngeal saliva, the viral load of COVID-19 patients was found to peak early at the time of symptom onset or at presentation, or even before symptom onset during the period of quarantine.

Although mandatory admission of all RT-PCR positive patients, including those subclinical or mildly symptomatic, has led to a shortage of negative pressure single isolation rooms, this arrangement which is mandated by public health ordinance allows early recruitment of patients for antiviral therapy. Ex vivo lung tissue explant challenged by SARS-CoV-2 showed that the innate immune response of lung tissue by interferons and inflammatory cytokines/chemokines were markedly suppressed.19 Studies of the SARS outbreak in 2003 showed that interferonbeta can be synergistic with ribavirin, and a combination of lopinavir-ritonavir and ribavirin can markedly improve the outcome of SARS patients in terms of mortality and respiratory failure.20 21 A recently published multicentre, prospective, open-label, randomised, phase 2 trial showed that triple antiviral therapy (interferon beta-1b, lopinavir-ritonavir, and ribavirin) was safe and superior to lopinavir-ritonavir alone in alleviating symptoms and shortening the duration of viral shedding and hospital stay in adult patients with mild to moderate COVID-19.18 The early admission of patients for assessment, antiviral therapy, and respiratory support may explain our very low crude fatality rate of less than 0.4% in Hong Kong. Although remdesivir was also shown to reduce time to recovery in a large randomised control, this drug is unlikely to be readily available in Hong Kong as the production cannot meet the huge demand.22 Therefore we are collecting convalescent plasma from recovered patients with high serum neutralising antibody titre and use it as a salvage therapy for those who do not respond to antiviral treatment including interferon beta-1b or remdesivir.

Hong Kong cannot be complacent, because just one super-spreading event in Amoy Garden during the 2003 SARS outbreak led to an overloading and paralysis of our hospital service. Fortunately, such events have not happened yet for COVID-19. The emergency evacuations of residents from buildings with faulty sewage vent pipes were wakeup calls for our urgent attention to the maintenance of such sewage systems. The cluster of seven COVID-19 cases in Luk Chuen House at Lek Yuen Estate, living in six units on different floors, could herald a major super-spreading event and should not be treated simply as just one more community cluster. Extensive RT-PCR testing for at least one person per thousand population per day for any mild respiratory symptoms should be conducted in all 18 districts to minimise the evolvement of super-spreading events. The SARS-CoV-2 will continue to circulate during the summer and may cause an explosive outbreak in winter because our herd immunity is very low. Even the seroprevalence among Hong Kong returnees from Hubei is only 3.8%.23 A safe and effective vaccine is unlikely to become widely available for another 12 months or more. Thus, SARS-CoV-2 will likely become another seasonal respiratory coronavirus circulating in humans for many years to come. More research on the animal source of SARS-CoV-2, pathogenesis and immunology, and effective control measures are urgently needed.

All authors contributed to the concept or design of the study, acquisition and analysis of the data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

The authors’ studies were partly supported by donations from Richard Yu and Carol Yu, May Tam Mak Mei Yin, the Shaw Foundation Hong Kong, Michael Seak-Kan Tong, Respiratory Viral Research Foundation, Hui Ming, Hui Hoy and Chow Sin Lan Charity Fund, Chan Yin Chuen Memorial Charitable Foundation, Marina Man-Wai Lee, the Hong Kong Hainan Commercial Association South China Microbiology Research Fund, the Jessie & George Ho Charitable Foundation, Perfect Shape Medical, and Kai Chong Tong; and by funding from the Consultancy Service for Enhancing Laboratory Surveillance of Emerging Infectious Diseases and Research Capability on Antimicrobial Resistance for the Department of Health of the Hong Kong Special Administrative Region Government; the Theme-Based Research Scheme (T11/707/15) of the Research Grants Council; Hong Kong Special Administrative Region; Sanming Project of Medicine in Shenzhen, China (no SZSM201911014); and the High Level-Hospital Program, Health Commission of Guangdong Province, China.

1. Chan JF, Yuan S, Kok KH, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet 2020;395:514-23. Crossref

2. Hung IF, Cheng VC, Li X, et al. SARS-CoV-2 shedding and seroconversion among passengers quarantined after disembarking a cruise ship: a case series. Lancet Infect Dis. In press.

3. To KK, Tsang OT, Leung WS, et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. Lancet Infect Dis 2020;20:565-74. Crossref

4. Cheung KS, Hung IF, Chan PP, et al. Gastrointestinal manifestations of SARS-CoV-2 infection and virus load in fecal samples from the Hong Kong cohort and systematic review and meta-analysis. Gastroenterology 2020 Apr 3. Epub ahead of print. Crossref

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6. Zhang Y, Xiao M, Zhang S, et al. Coagulopathy and antiphospholipid antibodies in patients with Covid-19. N Engl J Med 2020;382:e38. Crossref

7. Helms J, Kremer S, Merdji H, et al. Neurologic features in severe SARS-CoV-2 infection. N Engl J Med 2020 Apr 15. Epub ahead of print. Crossref

8. Tong JY, Wong A, Zhu D, Fastenberg JH, Tham T. The prevalence of olfactory and gustatory dysfunction in COVID-19 patients: A systematic review and metaanalysis. Otolaryngol Head Neck Surg 2020 May 5. Epub ahead of print. Crossref

9. Chung TW, Sridhar S, Zhang AJ, et al. Olfactory dysfunction in COVID-19 patients: observational cohort study and systematic review. Open Forum Infect Dis. In press.

10. Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet 2020;395:1054-62. Crossref

11. Kalligeros M, Shehadeh F, Mylona EK, et al. Association of obesity with disease severity among patients with COVID-19. Obesity (Silver Spring) 2020 Apr 30. Epub ahead of print. Crossref

12. Wu Z, McGoogan JM. Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: Summary of a report of 72 314 cases from the Chinese Center for Disease Control and Prevention. JAMA 2020 Feb 24. Epub ahead of print. Crossref

13. Ferrari R, Maggioni AP, Tavazzi L, Rapezzi C. The battle against COVID-19: mortality in Italy. Eur Heart J 2020 Apr 30. Epub ahead of print. Crossref

14. Lau SK, Woo PC, Li KS, et al. Severe acute respiratory syndrome coronavirus-like virus in Chinese horseshoe bats. Proc Natl Acad Sci U S A 2005;102:14040-5. Crossref

15. Cheng VC, Lau SK, Woo PC, Yuen KY. Severe acute respiratory syndrome coronavirus as an agent of emerging and reemerging infection. Clin Microbiol Rev 2007;20:660-94. Crossref

16. Cheng VC, Wong SC, Chuang VW, et al. The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2. J Infect 2020 Apr 23. Epub ahead of print. Crossref

17. To KK, Tsang OT, Chik-Yan Yip C, et al. Consistent detection of 2019 novel coronavirus in saliva. Clin Infect Dis 2020 Feb 12. Epub ahead of print. Crossref

18. Hung IF, Lung KC, Tso EY, et al. Triple combination of interferon beta-1b, lopinavir-ritonavir, and ribavirin in the treatment of patients admitted to hospital with COVID-19: an open-label, randomised, phase 2 trial. Lancet 2020;395:1695-704. Crossref

19. Chu H, Chan JF, Wang Y, et al. Comparative replication and immune activation profiles of SARS-CoV-2 and SARS-CoV in human lungs: an ex vivo study with implications for the pathogenesis of COVID-19. Clin Infect Dis 2020 Apr 9. Epub ahead of print. Crossref

20. Chu CM, Cheng VC, Hung IF, et al. Role of lopinavir/ritonavir in the treatment of SARS: initial virological and clinical findings. Thorax 2004;59:252-6. Crossref

21. Chen F, Chan KH, Jiang Y, et al. In vitro susceptibility of 10 clinical isolates of SARS coronavirus to selected antiviral compounds. J Clin Virol 2004;31:69-75. Crossref

22. Beigel JH, Tomashek KM, Dodd LE, et al. Remdesivir for the treatment of Covid-19—preliminary report. N Engl J Med 2020 May 22. Epub ahead of print.

23. To KK, Cheng VC, Cai JP, et al. Seroprevalence of SARSCoV- 2 in Hong Kong Special Administrative Region and our returnees evacuated from Hubei province of China: a multi-cohort study. Lancet Microbe. In press.

In this issue of Hong Kong Medical Journal, Teoh et al1 examine passive-positive organ donors in Hong Kong and potential means of engaging them. As the authors note, there is a significant mismatch between organ donors and patients awaiting transplant. In Hong Kong, more than 2000 dialysis patients are awaiting a kidney transplant, but there are fewer than 100 kidney transplants performed each year. Rather than investigating the reasons for refusing consent to donate deceased organs, the authors adopted another approach and instead surveyed passive-positive donors. These passive-positive donors refer to members of the public who support organ donation but have not registered as potential donors. The authors explored the reasons that these individuals gave for not registering. A key finding from the survey is that almost two thirds of people who are willing to donate their organs after death have not registered on the Centralised Organ Donation Register.1 The percentage of local passive-positive donors is even higher than that in the United States.

Why is the act of registration an important step to look into? A crucial aspect of facilitating behaviour change is making use of the commitment and consistency principle. If you want to lose weight, for instance, you should sign a contract with yourself (if not a contract with the fitness centre). Once you commit to a goal or an idea, you are much more inclined to follow through and achieve the goal and honour your commitment. As simple a step as it might seem, signing up as a donor turns out to be an important one.

Is the step of signing up as a donor going to make a huge difference? The answer is obviously ‘yes’, but it is not the only step. After you commit to a contract verbally or in writing, you should go one step further. Make the contract public, for all others to know, or else we you might simply back out of the deal. Unsurprisingly, human beings strive for consistency in our commitments, but more so when we are being watched. The most effective stamp to seal a contract is to share the contract on your social media platforms, and let others know, not only your next of kin. This is one of the best ways to enlist your friends and followers to hold you accountable. At the same time, this is a tool for someone who has signed up as an organ donor to encourage his or her followers to do the same.

How can social media help? The power of social media is immense. Social media platforms such as Facebook and Twitter have developed tools and public advocacy campaigns that can be used to engage and facilitate organ donation.2 For example, on the first day of launching the Facebook organ donor initiative (when members are allowed to specify ‘Organ Donor’ as part of their profile), there was a 21.1-fold increase in online organ donor registration rate in the United States.3

Is social media the only solution? Peer influence from social media on the donor registration rate is not the ultimate goal. Boosting the number of registered or prospective donors is insufficient, although the figures are easily measurable. Equally important is the value of being an organ donor. While the act of registration is the first step, that does not necessarily materialise as a donation if we cannot create a state of mind that donating organs can save lives. Organ donation will not happen if we cannot engage the prospective donor’s family members who might veto the donation plan. Additional interventions are needed to improve the public trust and foster belief in the meaningful act of donating organs.

What is the take-away message? We should heed the lesson from the study by Teoh et al1 regarding how to become a registered donor. However, continued efforts should be made to promote why people should to donate to save a life. We need a social movement to encourage the people of Hong Kong to talk about organ donation and end of life care matters, to share their view with their family, both informally via casual conversation, or better still, formally via registration. The expressed wish of a potential donor is very important in helping a family to agree to organ donation in a distressing time of a loved one who will sadly be passing away soon. It is difficult for the family to comprehend or to accept the situation. May they be comforted with knowing not all is lost. It is not only the end of one life, but the beginning of a new life for many recipients waiting for organ transplantation.

All authors contributed to the concept or design of the study, and critical revision of the manuscript for important intellectual content. KM Chow drafted the manuscript. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

This editorial received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

1. Teoh JY, Lau BS, Far NY, et al. Attitudes, acceptance, and registration in relation to organ donation in Hong Kong: a cross-sectional study. Hong Kong Med J 2020;26:192-200. Crossref

2. McCarthy M. Facebook and Twitter join US effort to attract a million new organ donor registrations. BMJ 2016;353:i3369. Crossref

3. Cameron AM, Massie AB, Alexander CE, et al. Social media and organ donor registration: the Facebook effect. Am J Transplant 2013;13:2059-65. Crossref

Miscarriage is the most common serious complication of pregnancy, occurring in approximately 20% of pregnancies.1 Miscarriage can cause anxiety and depression on the affected woman, and to the partner as well, albeit to a lower level.2

The ultrasound diagnosis of miscarriage has to be accurate. In 2011, a large multicentre study showed significant variation in the cut-off values for mean gestational sac diameter (MSD) and embryo crown-rump length (CRL) used to define miscarriage.3 Some cut-off criteria were found to be potentially unsafe with a risk of inadvertent termination of a potentially viable pregnancy.3 Since then, cut-off values of MSD and CRL defining miscarriage have been changed in the United Kingdom and the United States to ≥25 mm (without an obvious yolk sac) and ≥7 mm (without fetal heart activity), respectively.3 4 It was noted that in the guidelines for first-trimester ultrasound examination published by the Hong Kong College of Obstetricians and Gynaecologists in 2004, old cut-offs (20 mm for MSD and 5 mm for CRL) were used.5 A review of these cut-offs is required.

Transvaginal sonography is recommended to optimise the examination. Care must be taken when CRL measurement is close to any decision boundary for miscarriage or when MSD is being measured because of its high inter-observer limit of agreement, around 20%.6 When a miscarriage is found by one examiner, a repeat scan by another examiner is a reasonable safeguard.4 A repeat scan ≥7 days later will be appropriate if initial scan shows an embryo without heart activity or MSD ≥12 mm without embryo heart activity.4 A repeat scan ≥14 days will be appropriate if MSD <12 mm.4

Among women with intrauterine pregnancy of uncertain viability (PUV), the miscarriage rate is 49.3% to 52%.7 8 Prediction of pregnancy outcome is a challenge and is necessary because it can assist counselling and decide frequency of follow-up ultrasonography. Demographic factors, ultrasound and biochemical markers either used alone or in combination have been described in the literature to predict miscarriage.

Advanced maternal age (≥35 years) is a well-known risk factor because of the increase in chromosomal abnormalities with maternal age. Women who presented with vaginal bleeding, especially those having moderate or heavy bleeding, or blood clot per vagina were likely to subsequently miscarry.9 In this issue of the Hong Kong Medical Journal, Wan et al7 show similar findings. Interestingly, the authors found that moderate/ severe abdominal pain is a risk factor on univariate analysis, but this finding was not confirmed on multivariate analysis probably because vaginal bleeding was a cofounding factor.7

When ultrasound shows fetal cardiac activity, the subsequent rate of miscarriage is 5.2% to 10.4%.7 9 10 A meta-analysis of 18 eligible studies on ultrasound markers among 5584 women found that fetal bradycardia is the most significant marker, with a sensitivity of 84.2% in the prediction of miscarriage.11 A more recent study found that the combination of low fetal heart rate and small CRL increases the risk of subsequent pregnancy loss, from 5.0% to 21%.10 Because fetal heart rate varies with gestation, cut-offs for low fetal heart rate of ≤122, ≤123, and ≤158 beats per minute for gestational weeks 6, 7, and 8, respectively, have been proposed.10 Other investigators have suggested a single fetal heart rate cut-off at ≤110 or 100 beats per minute to predict miscarriage.11 12

Other ultrasonographic markers associated with miscarriage include a small difference between MSD and CRL,13 and abnormal size of yolk sac.14 Using three-dimensional ultrasonography, small gestational sac volume (below the 5th percentile) is associated with risk of miscarriage with odds ratio of 5.25.15 In a recent study of 61 miscarriages, abnormal size of gestational sac and yolk sac appeared as early as 6 weeks of gestation, followed by abnormal changes in fetal heart rate and CRL at 7 and 8 weeks.14 Although subchorionic haematoma was found to be a predictor of miscarriage in a meta-analysis11 and in the study by Wan et al,7 a recent study on pregnancies with detectable fetal heartbeat did not concur with these findings.10

A meta-analysis of 15 studies including 1263 women with threatened miscarriage found that serum CA 125 is the only serum marker that is useful in predicting outcome of a pregnancy with a viable fetus, whereas serum human chorionic gonadotropin and progesterone are not useful.16

Bottomley et al17 proposed a scoring system which included a combination of demographic and ultrasound variables to predict miscarriage. This scoring system can give an individualised probability of the pregnancy viability immediately following an ultrasound examination without the need of taking blood for biochemical markers and waiting for the results. In this study involving 1435 British women having detectable fetal heart activity and PUV, the use of this scoring system gave an area under the curve (AUC) of the receiver operating characteristic curve of 0.924.17 When this scoring system was validated, the accuracy was lower with AUC of 0.771 for the original study set of 376 women with PUV and AUC of 0.832 for another data set of 400 women with PUV.18 In their study, Wan et al report the first validation study of this scoring system on Chinese population, with AUC of 0.91 if only viable pregnancies were analysed.7 Although this scoring system is described as simple,7 17 its use requires extra time, and can be challenging to implement in a busy clinic setting. The use of this scoring system requires further studies in clinical settings.

Women with threatened miscarriage are at risk of anxiety and depression,19 and may react to miscarriage in different ways.20 Healthcare professionals should receive training on communication, and provide affected women with information and support in a sensitive and professional manner.18 20 During interpretation of ultrasound guidelines to diagnose miscarriage, other factors should be taken into consideration, including the woman’s desire to continue their pregnancy or to postpone intervention to achieve total certainty of miscarriage, and their acceptance of disadvantages of such postponement including emergency admission or procedure for heavy vaginal bleeding and anxiety.12

In summary, it is important to avoid misdiagnosis of miscarriage by using updated protocols and repeating scans if in doubt. Appropriate counselling on pregnancy outcome can be given after assessment of maternal age, amount of vaginal bleeding, fetal heart rate, CRL, preference on continuing the pregnancy, and anxiety level.

All authors contributed to concept, analysis or interpretation of data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had contributed to the manuscript, approved the final version for publication, and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

This editorial received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

1. Savitz DA, Hertz-Picciotto I, Poole C, Olshan AF. Epidemiologic measures of the course and outcome of pregnancy. Epidemiol Rev 2002;24:91-101. Crossref

2. Farren J, Mitchell-Jones N, Verbakel JY, Timmerman D, Jalmbrant M, Bourne T. The psychological impact of early pregnancy loss. Hum Reprod Update 2018;24:731-49. Crossref

3. Abdallah Y, Daemen A, Kirk E, et al. Limitations of current definitions of miscarriage using mean gestational sac diameter and crown-rump length measurements: a multicenter observational study. Ultrasound Obstet Gynecol 2011;38:497-502. Crossref

4. Preisler J, Kopeika J, Ismail L, et al. Defining safe criteria to diagnose miscarriage: prospective observational multicentre study. BMJ 2015;351:h4579. Crossref

5. Hong Kong College of Obstetricians and Gynaecologists (HKCOG). Guidelines for first trimester ultrasound examination: Part I. HKCOG guidelines Number 10 Part I. Available from: http://www.hkcog.org.hk/hkcog/Download/ Guidelines_for_First_Trimester_Ultrasound_Exam_ Part1_2004.pdf. Accessed 9 Mar 2020.

6. Pexsters A, Luts J, Van Schoubroeck D, et al. Clinical implications of intra- and interobserver reproducibility of transvaginal sonographic measurement of gestational sac and crown-rump length at 6-9 weeks' gestation. Ultrasound Obstet Gynecol 2011;38:510-5. Crossref

7. Wan OY, Chan SS, Chung JP, Kwok JW, Lao TT, Sahota DS. External validation of a simple scoring system to predict pregnancy viability in women presenting to an early pregnancy assessment clinic. HKMJ 2020;26:102-10. Crossref

8. Bottomley C, Van Belle V, Pexsters A, et al. A model and scoring system to predict outcome of intrauterine pregnancies of uncertain viability. Ultrasound Obstet Gynecol 2011;37:588-95. Crossref

9. Stamatopoulos N, Lu C, Casikar I, et al. Prediction of subsequent miscarriage risk in women who present with a viable pregnancy at the first early pregnancy scan. Aust N Z J Obstet Gynaecol 2015;55:464-72. Crossref

10. Devilbiss EA, Mumford SL, Sjaarda LA, et al. Prediction of pregnancy loss by early first trimester ultrasound characteristics. Am J Obstet Gynecol 2020 Feb 25. Epub ahead of print. Crossref

11. Pillai RN, Konje JC, Richardson M, Tincello DG, Potdar N. Prediction of miscarriage in women with viable intrauterine pregnancy—A systematic review and diagnostic accuracy meta-analysis. Eur J Obstet Gynecol Reprod Biol 2018;220:122-31. Crossref

12. Committee on Practice Bulletins—Gynecology. The American College of Obstetricians and Gynecologists Practice Bulletin no. 150. Early pregnancy loss. Obstet Gynecol 2015;125:1258- 67. Crossref

13. Bromley B, Harlow BL, Laboda LA, Benacerraf BR. Small sac size in the first trimester: a predictor of poor fetal outcome. Radiology 1991;178:375-7. Crossref

14. Detti L, Francillon L, Christiansen ME, et al. Early pregnancy ultrasound measurements and prediction of first trimester pregnancy loss: a logistic model. Sci Rep 2020;10:1545. Crossref

15. Wie JH, Choe S, Kim SJ, Shin JC, Kwon JY, Park IY. Sonographic parameters for prediction of miscarriage: role of 3-dimensional volume measurement. J Ultrasound Med 2015;34:1777-84. Crossref

16. Pillai RN, Konje JC, Tincello DG, Potdar N. Role of serum biomarkers in the prediction of outcome in women with threatened miscarriage: a systematic review and diagnostic accuracy meta-analysis. Hum Reprod Update 2016;22:228-39.Crossref

17. Bottomley C, Van Belle V, Kirk E, Van Huffel S, Timmerman D, Bourne T. Accurate prediction of pregnancy viability by means of a simple scoring system. Hum Reprod 2013;28:68-76. Crossref

18. Guha S, Van Belle V, Bottomley C, et al. External validation of models and simple scoring systems to predict miscarriage in intrauterine pregnancies of uncertain viability. Hum Reprod 2013;28:2905-11.Crossref

19. Zhu CS, Tan TC, Chen HY, Malhotra R, Allen JC, Østbye T. Threatened miscarriage and depressive and anxiety symptoms among women and partners in early pregnancy. J Affect Disord 2018;237:1-9. Crossref

20. National Institute for Health and Care Excellence (NICE). Ectopic pregnancy and miscarriage: diagnosis and initial management. NICE guideline [NG126]. Available from: https://www.nice.org.uk/guidance/ng126. Accessed 9 Mar 2020.