Kangqi Ng, MBBS; Beng Hoong Poon, MBBS, MPH, MMed (Family Med); Troy Hai Kiat Puar, MBBS; Jessica Li Shan Quah, MBBS; Wann Jia Loh, MBBS; Yu Jun Wong, MD; Thean Yen Tan, MBBCh; Jagadesan Raghuram, MB BCh BAO
Disclosures: Authors have disclosed no conflicts of interest. Forms can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L20-0175.
Table. Number of Nasopharyngeal Swabs in Exposed Health Care Workers, by Type of Procedure, Day After Last Exposure, and Type of Mask*
Karolina Akinosoglou, Charalambos Gogos
Dept of Internal Medicine and Infectious Diseases, University Hospital of pATRAS
March 17, 2020
Self-isolation of COVID-19-exposed asymptomatic health care workers (HCW): Wise or Worrying ?
Ng et al describe the clinical outcome of health care workers (HCW) who took care of a patient with COVID-19 pneumonia (1). Following 14-day isolation and serial PCR testing, none of the HCW involved were infected. However, as the pandemic progresses, and the need for increased testing and mitigation of HCW shortages increases, a number of concerns rise reagrding HCW exposure.Recent data has shown us that COVID-19 transmission can go undetected, by asymptomatic individuals (2). Exposed HCW could potentially become asymptomatic carriers, and, infect patients and/or colleagues. Hence, self-isolation is crucial to prevent transmission. However, in the case of HCW one should carefully weigh against the reality of the existing struggling health care system, that is required to respond to increased needs and workload. Where the fine line between risk to transmit to inpatient vulnerable groups, and establish the epidemic from “within”, and risk to push the system beyond repairable damage from existing non-sufficient personnel burn out, lies, remains elusive. Either way, the result would be the same, while it has become clear that health care resource availability, including HCW shows a clear association with disease mortality. (3) Even if one can afford asymptomatic exposed HCW self-isolation, timing of return to work is an open question, due to delayed virus shedding. Repeated negative testing has been adopted by many settings to optimize return to community, similar to follow up of discharged patients (4). However, in the case of exposed asymptomatic HCW, during the peak of a pandemic crisis, things can become more complex, since the actual risk and clinical impact of transmission via asymptomatic carriers still remains to be clearly quantified by mathematical models (5). Non-isolation and close monitoring via for example every other day screening of asymptomatic - high risk to develop symptoms - HCW could be an option in high income countries, that for example next-generation sequencing technology is available and affordable. Nonetheless, in the growing needs of an evolving epidemic, all settings should be managed as potentially resource-limited and any decision made should well justify its cost-effectiveness. Testing to confirm freedom-of-disease in asymptomatic individuals may come second, in view of the increased needs of diagnosis of symptomatic patients The days to come will challenge health care systems to unforeseen limits. Temporary self-isolation of asymptomatic HCW, should be well balanced against unbearable needs, and alternative ways of close monitoring should be explored, to ensure best outcomes
Facey Medical Group
March 19, 2020
Could you comment on whether the healthcare workers were using eye shields or other eye protection?
James Siu Ki Lau, Chi Kit Yuen
Ruttonjee Hospital, Hospital Authority, Hong Kong
Staying vigilant against COVID-19: Awareness and Proper Personal Protective Equipment
We read the published article by Kangqi Ng et al  titled "COVID-19 and the Risk to Health Care Workers: A Case Report" with great interest.
However, we would like to voice some concerns regarding the infection control in severe acute respiratory disease in health care workers which is seemingly substandard in the study.
Firstly, awareness of the COVID-19 is paramount. In Ng’s case, the surveillance of COVID-19, which should have been done on the first day after admission, was performed only after the patient was mechanically ventilated for 3 days and after extubation.
The delay in surveillance for COVID-19 also results in delay in contact tracing and isolation of unprotected HCWs (2). By the end of January in the Asia Pacific region, the highly infectious virus with significant morbidity and mortality COVID-19 (novel coronavirus at that time) was already on the news daily. The lack of awareness of the possibility of COVID-19 by the team could have devastating consequences such as spreading the disease into the community by healthcare workers. In addition to not allowing family/friends to visit the hospitals except in very special circumstances, hospitals in Hong Kong have exercised an enhanced surveillance strategy very early on in February to combat the spread of the disease in hospital wards and community. It screens all patients admitted with the diagnosis of pneumonia for COVID-19 in designated isolation wards.
Secondly, according to guidelines of both CDC and WHO (3), N95 or higher-level respirators should be used during aerosol-generating procedures. A large proportion of the 41 healthcare workers involved in caring the index patient were not in proper personal protective equipment when performing aerosol generating procedures. It is an unacceptable risk to any healthcare worker worldwide. In Tran’s study with WHO (4), they concluded aerosol generating procedures such as tracheal intubation, non-invasive ventilation, tracheotomy, and manual ventilation before intubation were associated with increased risk of SARS transmission to healthcare workers (4). Underlying reason for non-compliance to international guideline for proper application of PPE was not investigated in the study. Inadequate protection during aerosol generating procedures not just affects healthcare workers, but also their family, community, country and the world.
In conclusion, we agree with Ng that their negative yielding study is limited and we follow what most experts recommend so far on the use of N95 masks when performing aerosol generating procedures. We advocate staying vigilant against COVID-19 and not leaving our health and world to luck.
1. Ng K, Poon BH, Puar THK et al. COVID-19 and the Risk to Health Care Workers: A Case Report. Annals of Internal Medicine, 2020. doi:10.7326/L20-0175
2. World Health Organization. Infection prevention and control of epidemic-and pandemic-prone acute respiratory diseases in health care. June 2014. Accessed at https://apps.who.int/iris/bitstream/handle/10665/112656/9789241507134_eng.pdf?sequence=1 on 19 March 2020
3. World Health Organization. Rational use of personal protective equipment for coronavirus disease 2019 (COVID-19). 27 February 2020. Accessed at https://apps.who.int/iris/bitstream/handle/10665/331215/WHO-2019-nCov-IPCPPE_use-2020.1-eng.pdf on 19 March 2020.
4. Tran K, Cimon K, Severn M et al. (2012) Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: A systematic review. PLoS ONE, 7 (4):1-8.
Jacqueline Sedgwick, MD, MPH
Primary Care Physician
March 20, 2020
Prior randomized clinical trial demonstrated N95 superiority -decreased infection transmission including influenza
Please review: "A randomized clinical trial of three options for N95 respirators and medical masks in health workers", Am J Respir Crit Care Med Vol 187, Iss. 9, pp 960-966, May 1 2013 by C. Raina MacIntyre, Quanyi Wang, et al which found continuous use (not just for procedures, but for all possible exposures) to result in significantly lower rates of clinical respiratory infection in HCWs compared with targeted use or medical (surgical) masks.
Kangqi Ng, Troy Hai Kiat Puar; Jessica Li Shan Quah; Yu Jun Wong, Thean Yen Tan; Jagadesan Raghuram
Changi General Hospital, Singapore
March 24, 2020
We thank Karolina et al. for highlighting the need to balance pre-emptive quarantine of asymptomatic exposed health care workers (HCWs) and sustainable healthcare. As reliable data on the risk of asymptomatic transmission of this novel virus was unknown, we elected to quarantine all exposed HCWs until we were certain that they were not infected . Our strategy was disease containment to prevent further spread, as protecting HCWs prevents nosocomial transmission . Such an approach has been adopted in areas which had “flatten the curve” such as Korea and Taiwan. We acknowledge this approach may strain the existing health care resources. However, it is also paramount to ensure the safety and trust of our HCWs, especially with the mounting pressure from the increased work demand, inadequate resources and stigmatization from the community .
To address Lee et al. query, none of the HCWs involved in endotracheal intubation used eye shields. Our recommendation for HCWs during aerosol generating procedures (AGP) for suspected cases, included a powered-air purifying respirator, N95 mask, gloves and a full-body gown. For non-AGPs for suspected cases, eye protection, N95 mask, gloves, and a full-body gown were recommended.
We thank Siu et al. for the comments, and we acknowledge that protecting health care workers (HCWs) with personal protective equipment (PPE) is paramount. It is important that readers were aware that during the exposure to our index patient, Singapore was at Disease Outbreak Response System Condition (DORSCON) alert level yellow . However, without a travel history to China, or contact with COVID-19 patient, our patient did not meet national case definitions for COVID-19 testing. Following admission, enhanced testing for COVID-19 was initiated based on a revised national advisory for surveillance testing, and our patient subsequently found to be positive for COVID-19, 4 days after admission. During the early phase of the COVID-19 pandemic, several measures were set in place throughout Singapore, including ensuring excellent hand hygiene among HCWs, frequent disinfection of common areas, educating HCWs on PPE and restricting non-essential hospital visits for patients. Our hospital enforced standard droplet precautions and mandated the use of surgical masks in all clinical areas, with additional appropriate PPE (as stated above) when caring for suspect COVID-19 patients. We believe these measures collectively protected our HCWs in this exposure .
We appreciate Sedgwick et al. for highlighting a trial demonstrating the continuous use of N95 mask to prevent respiratory infections in HCWs. The practical use of PPE during a global pandemic, especially in a resource-limited setting, has been a point of debate. We must emphasize that adequate protection of HCWs should not be a debate on surgical masks or N95 masks alone, but rather a continuous, strict adherence to all protective measures, whenever possible. Finally, we emphasize that all institutions have the responsibility to equip all HCWs, our frontline warrior, with adequate PPE, in fighting this long-haul war against COVID-19.
1. Hu Z, Song C, Xu C et al. Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China. Sci China Life Sci 2020. Doi: 10.1007/s11427-020-1661-4
2. Cheng VCC, Wong S, Chen JHK et al. Escalating infection control response to the rapidly evolving epidemiology of the Coroavirus disease 2019 (COVID-19) due to SARS-COV-2 in Hong Kong. Infect Control Hosp Epidemiol 2020; 5:1-24
3. Su TP, Lien TC, Yang YC et al. Prevalence of psychiatric morbidity and psychological adaptation of the nurse in a structured SARS caring unit during outbreak: a prospective and periodic assessment study in Taiwan. J Psychiatr Res 2007; 41: 119-30
4. What do the different DORSCON levels mean. The colours describe the current disease outbreak situation and what needs to be done. https://www.gov.sg/article/what-do-the-different-dorscon-levels-mean. Accessed on 20 March 2020.
5. Atul Gawande. Keeping the Coronavirus from Infecting Health-Care Workers. What Singapore’s and Hong Kong’s success is teaching us about the pandemic. https://www.newyorker.com/news/news-desk/keeping-the-coronavirus-from-infecting-health-care-workers. Accessed 23 March 2020.
Ng K, Poon BH, Kiat Puar TH, et al. COVID-19 and the Risk to Health Care Workers: A Case Report. Ann Intern Med. 2020;:. [Epub ahead of print 16 March 2020]. doi: https://doi.org/10.7326/L20-0175
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