What is appropriate PPE? Lessons learned from healthcare worker COVID-19 infection in Hong Kong
The editorial on complete protection for healthcare workers (HCW) resonated with Liu and colleagues’ study and re-emphasized the effectiveness of appropriate personal protective equipment (PPE) on protecting frontline healthcare workers during the SARS-CoV-2 epidemic. We applaud the authors’ well-articulated arguments on defining the “appropriateness” of PPE based on evidence rather than irrational fears; yet, as we learned from the local experience in Hong Kong, especially those from the SARS-CoV-1 outbreak, appropriate PPE is only one of the few factors that could help protect HCWs.
In the immediate aftermath of the SARS-CoV-1 epidemic, the Hong Kong government commissioned an independent, cross-disciplinary expert review of the epidemic response. [1,2] Five major risk factors for HCWs post SARS were identified: (i) lack of training in infection control; (ii) inadequate supply and use of personal protective equipment (PPE); (iii) lack of infection control facilities (e.g. Isolation ward with negative pressure); (iv) increased workload, stress, and strain on the healthcare staff and system; and (v) the use of nebulizers that produces virus-rich aerosols. This review led to system-wide changes and significant improvements in the infection control and outbreak preparedness in Hong Kong’s public healthcare system. [1-3]
Seventeen years later, most of the five factors have been tackled in Hong Kong, but new issues have also emerged. The proportion of HCW COVID-19 cases among all cases ranges from as high as 16.6% in Philippines, 14% in Spain, 11% in Italy to as low as 1.2% in Indonesia or 1.7% in China (excluding Hubei).  Hong Kong so far has had only 2 cases in HCW up to 13 July among the total 1470 infections. One case was a 54-year-old female doctor who was tasked with issuing quarantine orders to visitors at Hong Kong International Airport in March ; the other was a 27-year-old paramedic who transported a woman diagnosed with COVID-19 from her home to hospital in June.  In both cases, the two HCWs wore surgical masks only.
These two infections remind us that the frontline of the SARS-CoV-2 has been expanded from hospitals to elsewhere, be it private clinic, airport, patients’ homes, or any public areas where the HCWs are needed. Different to SARS-CoV-1, this novel coronavirus can be transmitted from people without symptoms to others. As WHO admitted on 9 July, asymptomatic transmission and pre-symptomatic transmission are two distinctive features of SARS-CoV-2 in its newly updated guidelines.  Moreover, in the same guidelines, WHO also admitted airborne transmission of COVID-19 “cannot be ruled out” in in-door places.  Hence, it would be extremely difficult for HCWs to find an “appropriate” moment to be fully geared with PPE. Their frontline is everywhere.
So, the question is, once again, how do we define the “appropriateness” of PPE protection for HCWs? If the battle against COVID-19 continues, the definition should not just be derived from evidence, but also based on the views and perspectives of frontline HCWs as well. As the battle continues, in addition to the prolonged shortage of PPE, many HCWs may also suffer from the moral injury  that might affect their compliance with PPE requirement. More efficient and innovative ways of protecting HCWs, such as using AI robotics as substitutes under certain highly risky environment and timely psychological and emotional support for HCWs, need to be taken seriously.
Eliza Lai-Yi Wong, Dong Dong, Sian Griffiths, SF Lui, CT Hung, Hong Fung, EYY Chan, Eng-Kiong Yeoh
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Competing interests: No competing interests