To the Editor—We have previously reviewed a number of issues and challenges associated with in-flight medical emergencies.1 Recently, during a short flight from Hong Kong to Kaohsiung, one author (KLH) encountered a male passenger who summoned the flight attendants for medicine as he was having stomach cramps. The flight attendants rightly enquired about his history of drug allergy. Both antacids and paracetamol were available but only one should be offered; the man opted to take the paracetamol, and he seemed to feel better within a few minutes of taking it.

The man claimed that his stomach pain was triggered by eating and he was fine when empty-stomached. He denied any consumption of alcohol, tobacco, or over-the-counter medications. He claimed that the pain recurred approximately every month, but he had not seen any doctor about it. The author took this opportunity to provide health promotion education, noting the possibility of peptic ulcer disease and helicobacter infection, and recommending him to consult a doctor to follow up on the issue. The male passenger and his female companion appeared to be mistrustful at first but were at the end grateful for the health advice provided.

This episode exposed one of the fundamental health issues among Hong Kong citizens: living in a ‘sub-health’ state without seeking medical advice.2 This phenomenon is often due to people having a fear of doctors, antibiotics, steroids, or Western medicine.3 4 A sub-health state is characterised by some disturbances in psychological behaviours or physical characteristics, or in some indices of medical examination, with no typical pathologic features.5 A survey conducted by The University of Hong Kong in 2013 revealed that 97% of the surveyed Hong Kong citizens have experienced at least one sub-health symptom, and the most affected were aged 30 to 49 years, with an average of more than nine symptoms each.2 The impact should not be underestimated as 64% of the respondents reported that their daily lives were adversely affected.2

Public health promotion should target this sub-health state population, to prevent the potential development of chronic diseases. Health authorities should consider validated questionnaires to measure sub-health status in the primary care setting, so that interventions can be provided before it is too late.6

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

As an editor of the journal, KL Hon was excluded from the review process for this letter. The other author has disclosed no conflicts of interest.

1. Hon KL, Leung KK. Review of issues and challenges of practicing emergency medicine above 30,000-feet altitude: 2 anonymized cases. Air Med J 2017;36:67-70. Crossref

2. Public Opinion Programme, The University of Hong Kong. Survey on Hong Kong Citizens’ knowledge and opinions on sub-health. 2013. Available from: https://www.hkupop.hku.hk/english/report/subhealth/index.html. Accessed 24 Dec 2019.

3. Chen J, Xiang H, Jiang P, et al. The role of healthy lifestyle in the implementation of regressing suboptimal health status among college students in China: A nested case-control study. Int J Environ Res Public Health 2017;14. pii: E240. Crossref

4. Wu S, Xuan Z, Li F, et al. Work-recreation balance, healthpromoting lifestyles and suboptimal health status in southern china: a cross-sectional study. Int J Environ Res Public Health 2016;13. pii: E339. Crossref

5. Li G, Xie F, Yan S, et al. Subhealth: definition, criteria for diagnosis and potential prevalence in the central region of China. BMC Public Health 2013;13:446. Crossref

6. Yan YX, Liu YQ, Li M, et al. Development and evaluation of a questionnaire for measuring suboptimal health status in urban Chinese. J Epidemiol 2009;19:333-41. Crossref

To the Editor—Measles outbreaks have been reported in the Hong Kong Medical Journal in the past 2 years.1 2 Such outbreaks occur worldwide, including in countries where measles was previously considered eliminated. In March 2019, there was a measles outbreak at Hong Kong International Airport involving airport workers, some with documented evidence of at least two doses of measles vaccinations.3 Fortunately, the patients were all relatively young adults who experienced with mild symptoms, and the basic reproduction number of these cases was not high. In response to this outbreak, control measures at the airport included a vaccination programme and measles antibody testing for airport staff. The Hong Kong childhood immunisation schedule was also revised, so that the second dose of the MMRV (measles, mumps, rubella and varicella) vaccination is given at age 18 months (previously given at age 6 years) to enhance protection against measles.

Measles vaccination uptake rate is declining due to pockets of unvaccinated communities and anti-vaccination movements, both of which might have contributed to the recent outbreaks. To eliminate measles, a continuously high (>95%) level of vaccination coverage is required in all areas. Most recent outbreaks of measles in developed countries have been imported cases; thus, they are closely linked to the aviation industry. Early recognition of disease outbreak could prevent a global pandemic. Therefore, it is crucial to have contingency plans at every airport to prevent the spreading of contagious diseases. Travellers should ensure their vaccination status is up-to-date with two doses of measles vaccination; infants from 6 months of age should receive a supplementary dose of measles vaccine if they are travelling to areas with measles outbreaks.4 Affected patients, especially school-age children, should be isolated and quarantined at home for at least 4 days from the appearance of rash.

The 2019 measles outbreak saw a substantial increase in the number of measles cases reported worldwide relative to 2018. Such outbreaks will occur again if we do not learn from the past. The only hope to truly defeat measles is for humankind to work together.

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

As an Editor of the Journal, KL Hon was excluded from the review process for this letter. The other author has disclosed no conflicts of interest.

1. Hon KL, Leung AK, Leung K, Chan GC. Measles outbreak at an international airport: a Hong Kong perspective. Hong Kong Med J 2019;25:331-3. Crossref

2. 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

3. Centre for Health Protection, Hong Kong SAR Government. Daily update on measles situation in Hong Kong. Available from: https://www.chp.gov.hk/files/pdf/daily_update_on_measles_cases_in_2019_eng.pdf. Accessed 6 Dec 2019.

4. World Health Organization. WHO advice for international travel in relation to measles. 2019. Available from: https://www.who.int/ith/WHO-advice-for-international-travel-in-relation-to-measles.pdf?ua=1. Accessed 6 Dec 2019.

To the Editor—With large number of deaths in many countries owing to the coronavirus disease 2019 (COVID-19) pandemic, there is a place for palliative care to alleviate suffering and uphold dignity for these patients.1 However, the small number of deaths and the primary goal to save lives has limited the referral of patients with COVID-19 in Hong Kong for palliative care. Nevertheless, medical professionals should be well prepared to serve those who would die of COVID-19 as well as from unrelated causes.2

Without palliative care units, although patients with advanced life-limiting illnesses could be admitted to acute medical beds with support from the palliative consultative service, the aggressiveness of medical treatment and provision of compassionate care might not be appropriate in acute settings. This can jeopardise the quality of care, especially for patients with complex needs, challenging symptom burden, and complicated grieving families. Thus, both palliative in-patient and consultative services are complementary and both are needed in acute hospitals.3 There is ample evidence that palliative care provides good outcomes, including better quality of life, shortened length of stay in hospital, increased home death, and more cost-effective acute care.4 5 6 Deprioritising palliative care would imply that the local health authority overlooks the holistic needs of people with life-limiting illnesses.

The initial strategy adopted by the Hospital Authority for quarantining all patients with COVID-19 in acute hospitals, regardless of their disease severity, was successful in containing the spread of virus. However, for patients with COVID-19 and only minor or no symptoms, compulsory home or camp quarantine with ambulatory medical support may achieve equal success, sparing the well-equipped cohort wards and intensive care units for those in serious and critical conditions, without sacrificing patients with other medical conditions.

A blanket method of rationing in which individuals are categorised according to factors such as age, physical or mental disability, or those under palliative care, should not be adopted during a pandemic.7 8 Categorical exclusions may be interpreted by the public to mean that certain groups of patient are “not worth treating”, leading to the perception of unfairness and distrust. Palliative care patients are often the most vulnerable and neglected group in the medical field. Nevertheless, palliative care is about more than medical treatment. A case-by-case approach is a better and more humane way to preserve the dignity of all groups of patients.

The author drafted the letter. The author approved the final version for publication and takes responsibility for its accuracy and integrity.

The author declared no conflicts of interest for the authorship and publication of this letter.

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

1. Humanitarian Health Ethics Research Group. Alleviating suffering and upholding dignity in the midst of CoViD-19 response: a place for palliative care. 31 Mar 2020. Available from: https://www.phpc.cam.ac.uk/pcu/files/2020/04/PallcareCovid_Recommendations_FINAL.pdf. Accessed 30 Apr 2020.

2. Downar J, Seccareccia D, Associated Medical Services Inc. Educational Fellows in Care at the End of Life. Palliating a pandemic: “All patients must be cared for”. J Pain Symptom Manage 2010;39:291-5. Crossref

3. Gaertner J, Frechen S, Sladek M, Ostgathe C, Voltz R. Palliative care consultation service and palliative care unit: why do we need both? Oncologist 2012;17:428-35. Crossref

4. Eti S, O’Mahony S, McHugh M, Guilbe R, Blank A, Selwyn P. Outcomes of the acute palliative care unit in an academic medical center. Am J Hosp Palliat Care 2014;31:380-4. Crossref

5. Grogan E, Paes P, Peel T. Excellence in cost-effective inpatient specialist palliative care in NHS—a new model. Clin Med (Lond) 2016;16:7-11. Crossref

6. Hui D, Elsayem A, Palla S, et al. Discharge outcomes and survival of patients with advanced cancer admitted to an acute palliative care unit at a comprehensive cancer center. J Palliat Med 2010;13:49-57. Crossref

7. Daly DJ. Guidelines for rationing treatment during the COVID-19 crisis: a catholic approach. Health Prog 2020;101. Available from: https://www.chausa.org/publications/health-progress/current-issue. Accessed 30 Apr 2020.

8. Emanuel EJ, Persad G, Upshur R, et al. Fair allocation of scarce medical resources in the time of COVID-19. N Engl J Med 2020;382:2049-55. Crossref

To the Editor—We are most appreciative of the communication and comments by Ng et al1 which draws our attention to the seminal works and landmark paper by Kwong et al2 in which no less than seven bacteria are listed to have significant association with colon cancer, with Clostridium septicum (hazard ratio [HR]=17.1), Gamella morbillorum (HR=15.2), and Streptococcus gallolyticus or Streptococcus bovis (HR=5.73) high on the list. Others have reported cancer association with even seemingly benign organisms such as Enterococcus faecalis or Escherichia coli.3 Conceivably, and with further validation, circulating intestinal bacteria may eventually become a new biomarker for colonic cancer especially at a pre-symptomatic stage. But here we need a word of caution. With an early doubling time of over 30 months, the early growth of a colorectal cancer has been shown to be slow.4 Early detection of a slow-growing cancer warrants other considerations. In our ageing population it is not too uncommon to see a patient in advanced age with multiple co-morbidities and limited life expectancy. In such cases further extensive investigations may not be justified. To complete the story of the patient with S gallolyticus septicaemia we barely mentioned in an earlier communication,5 he was a 91-year-old Caucasian missionary, with advanced atherosclerotic disease, severe dementia, recurrent heart failure, deteriorating renal function, and an abdominal aneurysm for which interventional treatment was rejected. The question of colonoscopy was raised but vetoed by all parties concerned. His septicaemia was successfully controlled by penicillin and his constipation well relieved by judicious enemas instead of lactulose. He lived for another 9 months, and eventually died of heart failure. From the holistic perspective, if he had an occult colonic cancer, he probably died with it, rather than of it.

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 conflict of interest.

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

1. Ng SC, Wong HK, So CK, et al. Streptococcus bovis bacteremia should be investigated for early detection of colorectal pathology. Hong Kong Med J 2019;25:414. Crossref

2. Kwong TN, Wang X, Nakatsu G, et al. Association between bacteremia from specific microbes and subsequent diagnosis of colorectal cancer. Gastroenterology 2018;155:383-90.e8. Crossref

3. Sears CL, Garrettt WS. Microbes, microbiota, and colon cancer. Cell Host Microbe 2014;15:317-28. Crossref

4. Matsui T, Yao T, Iwashita A. Natural history of early colorectal cancer. World J Surg 2000;24:1022-8. Crossref

5. Leung JSM. Streptococcal gallolyticus endocarditis—an uncommon but serious complication of constipation management. Hong Kong Med J 2019;25:257. Crossref

To the Editor—Recently, some patients have tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using reverse transcription polymerase chain reaction despite earlier recovery from coronavirus disease 2019 (COVID-19). Among 111 recovered patients, 5% in China and 10% in South Korea have tested positive again.1 2 Typically, after recovery from a viral infection, the body produces antibodies that can resist reinfection from the same virus.3 There is evidence that COVID-19 reinfection is not possible within 7 to 10 days.4 A Chinese study on COVID-19 involving primates showed no viral replication in all primary tissue compartments at 5 days post-reinfection, indicating that the primary infection of SARS-CoV-2 could prevent subsequent infections.5

Positive reverse transcription polymerase chain reaction test results from the patients who have recovered from COVID-19 are possibly attributed to:

(i) The virus persisting within body. Patients with severe acute respiratory syndrome have reported positive results in tests for the virus in faeces 2 months after onset.6 Respiratory tract secretion tests have also shown positive results and high concentrations of the virus for 3 weeks after onset.7 Virus shedding gradually decreases towards the detection limit around 21 days after onset.8
(ii) Cross-contamination from another betacoronavirus.9
(iii) False positive results.10
(iv) Incorrect sample collection methods. The sample may not be collected widely and deeply enough to include the virus, resulting in a negative result.11 Furthermore, the virus binds to the angiotensin-converting enzyme 2 receptor and remains in the throat, but the test includes only the upper respiratory tract where the amount of virus has been reduced.12 When clinical symptoms are stable, the virus can still spread and infect different organs such as the spleen, hilar lymph nodes, kidneys, liver, and brain; in such cases deep throat saliva test may not be able to detect SARS-CoV-2 infection.13

There is currently no supporting evidence for COVID-19 reinfection after recovery. However, it is important to ensure that samples are collected correctly and test procedures are followed properly. In accordance with the advice of the World Health Organization, patients with no clinical symptoms can be discharged from the hospital if they test negative for SARS-CoV-2 infection at least twice after a 24-hour interval.14

All authors contributed to the concept 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.

The authors have no conflicts of interest to disclose.

The authors received no funding source/grants or other materials support for this work.

1. Mystery in Wuhan: Recovered coronavirus patients test negative…then positive. 27 March 2020. Available from: https://www.npr.org/sections/goatsandsoda/2020/03/27/822407626/ mystery-in-wuhan-recovered-coronavirus-patients-test-negative-then-positive. Accessed 22 Apr 2020.

2. Over 110 people retest positive for coronavirus: authorities. 12 April 2020. Available from: http://www.koreaherald.com/view.php?ud=20200412000213&np=3&mp=1. Accessed 22 Apr 2020.

3. McCullough KC. Immune response in vitro. In: Delves PJ, Roitt IM, editors. Encyclopedia of Immunology (second edition). London: Academic Press; 1998: 1233-43. Crossref

4. Can you be re-infected after recovering from coronavirus? Here’s what we know about COVID-19 immunity. 13 April 2020. Available from: https://time.com/5810454/coronavirus-immunity-reinfection. Accessed 22 Apr 2020.

5. Bao L, Deng W, Gao H, et al. Reinfection could not occur in SARS-CoV-2 infected rhesus macaques. BioRxiv [Preprint] 2020. Available from: https://doi.org/10.1101/2020.03.13.990226. Accessed 22 Apr 2020.

6. Isakbaeva ET, Khetsuriani N, Suzanne Beard R, et al. SARS-associated coronavirus transmission, United States. Emerg Infect Dis 2004;10:225-31. Crossref

7. Chan JF, Yip CC, To KK, et al. Improved molecular diagnosis of COVID-19 by the novel, highly sensitive and specific COVID-19-RdRp/Hel real-time reverse transcription-PCR assay validated in vitro and with clinical specimens. J Clin Microbiol 2020;58:e00310-20. Crossref

8. He X, Lau EH, Wu P, et al. Temporal dynamics in viral shedding and transmissibility of COVID-19. Nat Med 2020 Apr 15. Epub ahead of print.

9. Coronaviridae Study Group of the International Committee on Taxonomy of Viruses. The species severe acute respiratory syndrome–related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2. Nat Microbiol 2020;5:536-44. Crossref

10. Lan L, Xu D, Ye G, et al. Positive RT-PCR test results in patients recovered from COVID-19. JAMA 2020 Feb 27. Epub ahead of print. Crossref

11. Yi Y, Lagniton PN, Ye S, Li E, Xu RH. COVID-19: what has been learned and to be learned about the novel coronavirus disease. Int J Biol Sci 2020;16:1753-66. Crossref

12. Jia HP, Look DC, Shi L, et al. ACE2 receptor expression and severe acute respiratory syndrome coronavirus infection depend on differentiation of human airway epithelia. J Virol 2005;79:14614-21. Crossref

13. Yao XH, Li TY, He ZC, et al. A pathological report of three COVID-19 cases by minimally invasive autopsies [in Chinese]. Zhonghua Bing Li Xue Za Zhi 2020;49:E009. Crossref

14. Coronavirus disease (COVID-19) technical guidance: Laboratory testing for 2019-nCoV in humans. 8 April 2020. Available from: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/technical-guidance/laboratory-guidance. Accessed 22 Apr 2020.