To the Editor—Coronavirus disease 2019 (COVID-19) vaccine hesitancy was high initially1 but persists in Hong Kong. As of 2 January 2023, 93.0% and 83.3% of the population had received the second and third doses of the COVID-19 vaccine, respectively.2 However, vaccination uptake for the third dose was only 77.06% for age-group of 12-19 years and 30.92% for those aged 3-11 years.2 The government intends to lower the vaccine pass age limit to 5 years and allow schools to hold full-day face-to-face classes only if 90% of students have received three doses of vaccine before 1 November 2022. According to one study,3 there are four reasons for parental vaccine refusal: religious beliefs, personal beliefs or philosophical reasons, safety concerns, and a desire for more information from healthcare providers. Clearly the reason for the low vaccination rate in Hong Kong is mainly due to safety concerns. The Centre for Health Protection of the Department of Health publishes public health recommendations for the Hong Kong Childhood Immunisation Programme. Advised vaccines from birth onwards include Bacillus Calmette-Guérin, hepatitis B, and diphtheria, tetanus, acellular pertussis and inactivated poliovirus vaccines. Although the side-effects of these vaccines, such as low fever, redness, and a sore arm, are well known, parents do not oppose their administration. We recommend that the Department of Health collaborate with the Education Bureau to implement measures that can improve vaccine uptake. These include: provision of more scientific information, educational and on-site vaccination interventions to schools with a low vaccination rate,4 measures to enhance the biological literacy of school children to encourage vaccination, rapid response by healthcare professionals to dispel rumours and conspiracy theories, education of parents about the benefits of vaccination, and provision of educational seminars via Zoom as continued regular education has been shown to improve the success of vaccination programmes.5 In addition, the Centre for Health Protection may consider other options such as delivering a fractional dose to minimise the side-effects. Another study6 suggests that using an intradermal fractional dose (10-20% the amount of the original dose) vaccination using a microneedle patch can result in better immunogenicity. Side-effects are the most common concern among those who are hesitant or opposed to vaccination. As the safety profile of fractional doses is comparable to that of a regular dose,7 fractional dosages may help combat such hesitancy.

All authors contributed to the drafting of the letter and critical revision for important intellectual content. All authors approved the final version for publication, and take responsibility for its accuracy and integrity.

The authors have declared no conflicts of interest.

The work of this letter was supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region (Project No.: CityU 11303521).

1. Yu BY, Lam JC, Lam SC, et al. COVID-19 vaccine hesitancy and resistance in an urban Chinese population of Hong Kong: a cross-sectional study. Hum Vaccin Immunother 2022;18:2072144. Crossref

2. Hong Kong SAR Government. Hong Kong vaccination dashboard. Available from: https://www.covidvaccine.gov.hk/en/dashboard. Accessed 2 Jan 2023.

3. McKee C, Bohannon K. Exploring the reasons behind parental refusal of vaccines. J Pediatr Pharmacol Ther 2016;21:104-9. Crossref

4. Gellert P, Bethke N, Seybold J. School-based educational and on-site vaccination intervention among adolescents: study protocol of a cluster randomised controlled trial. BMJ Open 2019;9:e025113. Crossref

5. Akther T, Nur T. A model of factors influencing COVID-19 vaccine acceptance: a synthesis of the theory of reasoned action, conspiracy theory belief, awareness, perceived usefulness, and perceived ease of use. PLoS One 2022;17:e0261869. Crossref

6. Migliore A, Gigliucci G, Di Marzo R, Russo D, Mammucari M. Intradermal vaccination: a potential tool in the battle against the COVID-19 pandemic? Risk Manag Healthc Policy 2021;14:2079-87. Crossref

7. Yang B, Huang X, Gao H, Leung N, Tsang T, Cowling B. Immunogenicity, efficacy, and safety of SARS-CoV-2 vaccine dose fractionation: a systematic review and meta-analysis. BMC Med 2022;20:409. Crossref

To the Editor—To combat the fifth wave of the coronavirus disease (COVID) pandemic, the Hospital Authority re-opened the Community Treatment Facility at the Asia World Expo (AWE) in January 2022 to help alleviate the burden on hospitals.

Clinical mindset while working at a makeshift hospital requires some modification. For instance, the threshold at which to transfer a deteriorating patient must be lower, since the AWE is not equipped to care for ill patients. For example, there is no piped oxygen supply. Since oxygen cylinders can provide support for only a limited duration when used in high-flow mode, and oxygen concentrators cannot support flow of more than 4 L/min, resuscitation is more difficult at the AWE.1 In the author’s experience, a patient with SaO₂ <94% on room air already warrants serious consideration for transfer to another unit.

The choice of therapeutics such as intravenous antibiotics will depend not only on the patient’s susceptibility but also on ease of use so that workload for nurses is minimised. An antibiotic that can be injected once daily is preferable to a 12-hourly option; and an antibiotic that can be directly injected intravenously is preferable to one that needs pre-dilution with normal saline.

Cough is a prevalent complaint amongst patients attending the treatment facility at the AWE. Chinese herbal medicine provides good symptomatic relief and was welcomed by many patients. For patients with a history of benign prostate hyperplasia, the author will first consult the Chinese Medicine team to establish whether any herbal medicine has the ingredient ephedra alkaloid (麻黃).2 The latter contains ephedrine and may aggravate lower urinary tract symptoms.3 The author learnt from the Chinese Medicine team that the cough remedy “止嗽散合獨參湯加減” contains only a small amount of ephedra, and is safe for use in patients with lower urinary tract symptoms.

Setting up the AWE has been complex with many logistical issues. The administration responsible for the setting up of AWE should be commended for their effort.

The author contributed to the drafting of the letter and critical revision for important intellectual content. The author approved the final version for publication and takes responsibility for its accuracy and integrity.

The author has disclosed no conflicts of interest.

1. Jain R, Sharma C. Oxygen supply in hospitals: requisites in the current pandemic. Anesth Essays Res 2021;15:253-6. Crossref

2. Zhao W, Deng AJ, Du GH, Zhang JL, Li ZH, Qin HL. Chemical constituents of the stems of Ephedra sinica. J Asian Nat Prod Res 2009;11:168-71. Crossref

3. Balyeat RM, Rinkel HJ. Urinary retention due the use of ephedrine. JAMA 1932;98:1545-6. Crossref

To the Editor—Since the review on the immune modulating effects of vitamin D in coronavirus disease 2019 (COVID-19) infection by Kaler et al1 last year, there has been an open-label trial showing positive effects of vitamin D supplementation in COVID-19 patients in Spain. Out of 838 COVID-19 in patients, 447 were routinely given calcifediol (25-hydroxycholecalciferol) 532 μg on admission, and 266 μg on day 3,7,15 and 30. The treatment group had very significantly lower rates of intensive care unit admission (4.5% vs 21%) and death (4.7% vs 15.9%).2 In contrast, two randomised trials of a single large dose of vitamin D3 on admission in moderate to severe COVID-19 patients have showed no significant benefits.3 The discrepant results may be due to differences in vitamin D formulations. As compared with vitamin D3, calcifediol does not require hydroxylation in liver which is often impaired in acute illness. Therefore, vitamin D supplementation should preferably be started before exposure to COVID-19. Older people who seldom go outside, especially those in old age homes, have high prevalence of vitamin D deficiency. Indeed, an expert group recommended routine use of vitamin D3 1000 units daily in old age homes.4 A randomised trial of vitamin D3 in older people showed that doses up to 2000 units daily for four months was very safe.5 In the midst of the pandemic, I recommend vitamin D3 2000 units once daily in homebound older people to prevent COVID-19 infection and its complications, especially those who are not fully vaccinated.

The author contributed to the Letter, approved the final version for publication, and takes responsibility for its accuracy and integrity.

The author has disclosed no conflicts of interest.

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

1. Kaler J, Hussain A, Azim D, Ali S, Nasim S. Optimising vitamin D levels in patients with COVID-19. Hong Kong Med J 2021;27:154-6.Crossref

2. Nogues X, Ovejero D, Pineda-Moncusí M, et al. Calcifediol treatment and COVID-19-related outcomes. J Clin Endocrinol Metab 2021;106:e4017-27. Crossref

3. Cannata-Andía JB, Díaz-Sottolano A, Díaz-Sottolano A, et al. A single-oral bolus of 100,000 IU of cholecalciferol at hospital admission did not improve outcomes in the COVID-19 disease: the COVID-VIT-D-a randomised multicentre international clinical trial. BMC Med 2022;20:83. Crossref

4. Rolland Y, de Souto Barreto P, Abellan Van Kan G, et al. Vitamin D supplementation in older adults: searching for specific guidelines in nursing homes. J Nutr Health Aging 2013;17:402-12. Crossref

5. Schwartz JB, Kane L, Bikle D. Response of vitamin D concentration to vitamin d3 administration in older adults without sun exposure: a randomized double-blind trial. J Am Geriatr Soc 2016;64:65-72. Crossref

To the Editor—On 22 February 2020, news media reported an unattended 4-year-old girl who fell to her death from a window in her 15th-floor flat.1 The Hong Kong Medical Journal has reported childhood deaths due to accidents and injuries.2 3 4 Injury is a major health problem for Hong Kong children and has surpassed infectious diseases as the leading cause of childhood mortality in Hong Kong.2 5 Approximately 2.9% of children will be admitted to hospital for an injury at least once before their fourth birthday. In a city with many high-rise residential buildings, the risk of falling from height is relatively high, and invariably fatal. Nevertheless, even small falls occurring indoors can lead to severe head injuries or death.6 Preventive measures against childhood injury in Hong Kong are reactive in nature, piecemeal, and usually not subject to evaluation.2 It is recommended that childhood injury prevention be given prime consideration in all policies involving children. Most accidents and injuries may potentially be preventable. Primary prevention by health promotion and public health measures can save lives. Moreover, prompt and effective on-scene cardiopulmonary resuscitation may offer chances of survival and better outcomes for patients after falls.

Both authors contributed to the drafting of the letter and critical revision for important intellectual content. Both authors approved the final version for publication and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

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

1. Girl, 4, falls to death from 15th floor flat in Hong Kong, father suspected to have left daughters unattended. Available from: https://www.scmp.com/news/hong-kong/law-and-crime/article/3051828/girl-4-falls-death-15th-floor-flat-hong-kong-father. Accessed 22 Feb 2020.

2. Hong Kong Children Injury Prevention Research Group. Childhood injury prevention in Hong Kong. Hong Kong Med J 1998;4:400-4.

3. Hon KL, Ku AS. Tragic deaths by choking in healthy children. Hong Kong Med J 2019;25:413. Crossref

4. Hon KL, Chan J, Cheung KL. Head injuries after short falls: different outcomes despite similar causes. Hong Kong Med J 2010;16:497-8.

5. Hon KL, Leung TF, Chan SY, Cheung KL, Ng PC. Indoor versus outdoor childhood submersion injury in a densely populated city. Acta Paediatr 2008;97:1261-4. Crossref

6. Hon KL, Leung TF, Cheung KL, et al. Severe childhood injuries and poisoning in a densely populated city: where do they occur and what type? J Crit Care 2010;25:175.e7-12. Crossref

To the Editor—Although many research endeavours focus on the microbiology, epidemiology, and molecular characterisation of extended-spectrum beta-lactamase-producing and carbapenem-resistant Gram-negative bacteria, few studies aim to assess the impact of these resistance traits on patient outcomes. Therefore, Man et al1 should be applauded for linking antimicrobial resistance in Klebsiella pneumoniae strains with the risk of inappropriate empirical treatment and infection-related mortality.1 The role of empirical antibiotics in septic patients was also highlighted as a key consideration. However, although extended-spectrum beta-lactamase-producing or carbapenem-resistant K pneumoniae isolates were associated with a greater risk of inappropriate empirical treatment, and subsequently with significantly higher 90-day and hospital mortalities, the manuscript would benefit from delineating these two groups of resistant bacteria, as well as from including Pitt bacteraemia scores. Moreover, a paramount study by Patel et al2 showed that even appropriate empirical treatment is often not associated with improved survival among patients with carbapenem-resistant K pneumoniae infections. Also, heteroresistance is an under-recognised phenomenon that may render K pneumoniae strains resistant to antibiotics (despite in vitro susceptibility) and, in turn, confound any steadfast conclusions.3 This is why linking patient-level microbiology data with clinical records and patient outcomes in different settings will be a priority in years to come, as evidenced by trailblazing Global Research on AntiMicrobial resistance (GRAM) Project led by the Institute for Health Metrics and Evaluation (University of Washington) and the Big Data Institute (University of Oxford).4 The highest burden of sepsis-related deaths was already demonstrated in locations least equipped to identify or treat sepsis5; thus, going forward, studies akin to Man et al1 analysing individual-level data will be indispensable.

The author had full access to the data, contributed to the letter, approved the final version for publication, and takes responsibility for its accuracy and integrity.

The author has no conflicts of interest to disclose.

The author is involved in the Global Research on AntiMicrobial resistance (GRAM) Project, Institute for Health Metrics and Evaluation, University of Washington, Seattle, United States.

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

1. Man MY, Shum HP, Li KC, Yan WW. Impact of appropriate empirical antibiotics on clinical outcomes in Klebsiella pneumoniae bacteraemia. Hong Kong Med J 2021;27:247-57. Crossref

2. Patel G, Huprikar S, Factor SH, Jenkins SG, Calfee DP. Outcomes of carbapenem-resistant Klebsiella pneumoniae infection and the impact of antimicrobial and adjunctive therapies. Infect Control Hosp Epidemiol 2008;29:1099-106. Crossref

3. Band VI, Weiss DS. Heteroresistance: a cause of unexplained antibiotic treatment failure? PLoS Pathog 2019;15:e1007726. Crossref

4. Schnall J, Rajkhowa A, Ikuta K, Rao P, Moore CE. Surveillance and monitoring of antimicrobial resistance: limitations and lessons from the GRAM project. BMC Med 2019;17:176. Crossref

5. Rudd KE, Johnson SC, Agesa KM, et al. Global, regional, and national sepsis incidence and mortality, 1990-2017: analysis for the Global Burden of Disease Study. Lancet 2020;395:200-11. Crossref