key: cord-0729707-znnfobfj
authors: Cheng, Vincent Chi-Chung; Wong, Shuk-Ching; Tong, Danny Wah-Kun; Chuang, Vivien Wai-Man; Chen, Jonathan Hon-Kwan; Lee, Larry Lap-Yip; To, Kelvin Kai-Wang; Hung, Ivan Fan-Ngai; Ho, Pak-Leung; Yeung, Deacons Tai-Kong; Chung, Kin-Lai; Yuen, Kwok-Yung
title: Multipronged infection control strategy to achieve zero nosocomial coronavirus disease 2019 (COVID-19) cases among Hong Kong healthcare workers in the first 300 days of the pandemic
date: 2021-03-19
journal: Infection control and hospital epidemiology
DOI: 10.1017/ice.2021.119
sha: 522ad5e90d5f653f25440602a95b3b6dcf519e7e
doc_id: 729707
cord_uid: znnfobfj

BACKGROUND: Nosocomial outbreaks leading to healthcare worker (HCW) infection and death have been increasingly reported during the coronavirus disease 2019 (COVID-19) pandemic. OBJECTIVE: We implemented a strategy to reduce nosocomial acquisition. METHODS: We summarized our experience in implementing a multipronged infection control strategy in the first 300 days (December 31, 2019, to October 25, 2020) of the COVID-19 pandemic under the governance of Hospital Authority in Hong Kong. RESULTS: Of 5,296 COVID-19 patients, 4,808 (90.8%) were diagnosed in the first pandemic wave (142 cases), second wave (896 cases), and third wave (3,770 cases) in Hong Kong. With the exception of 1 patient who died before admission, all COVID-19 patients were admitted to the public healthcare system for a total of 78,834 COVID-19 patient days. The median length of stay was 13 days (range, 1–128). Of 81,955 HCWs, 38 HCWs (0.05%; 2 doctors and 11 nurses and 25 nonprofessional staff) acquired COVID-19. With the exception of 5 of 38 HCWs (13.2%) infected by HCW-to-HCW transmission in the nonclinical settings, no HCW had documented transmission from COVID-19 patients in the hospitals. The incidence of COVID-19 among HCWs was significantly lower than that of our general population (0.46 per 1,000 HCWs vs 0.71 per 1,000 population; P = .008). The incidence of COVID-19 among professional staff was significantly lower than that of nonprofessional staff (0.30 vs 0.66 per 1,000 full-time equivalent; P = .022). CONCLUSIONS: A hospital-based approach spared our healthcare service from being overloaded. With our multipronged infection control strategy, no nosocomial COVID-19 in was identified among HCWs in the first 300 days of the COVID-19 pandemic in Hong Kong.

386 HCWs were infected and 8 died as a result of nosocomial acquisition of SARS-CoV-1. Since the outbreak of communityacquired pneumonia in Wuhan, Hubei province, was officially announced on December 31, 2019 (day 1), 9 our priority has been to ensure the safety of our HCWs during the COVID-19 pandemic. To achieve zero nosocomial COVID-19 cases among HCWs, we implemented a multipronged infection control strategy to minimize the risk of nosocomial COVID-19 in Hong Kong. A hospital-based approach was adopted in which symptomatic and asymptomatic COVID-19 patients were managed in airborne infection isolation rooms (AIIRs) in hospitals under the governance of Hospital Authority, and these patients were subsequently diverted to the community isolation facility (CIF) and the community treatment facility (CTF), also under the management of the Hospital Authority. 10 

All newly diagnosed COVID-19 patients were managed inside AIIRs in hospitals or were diverted to the CIF and CTF under the governance of the Hospital Authority. Laboratory diagnosis of COVID-19 is based on reverse transcription-polymerase chain reaction (RT-PCR) of SARS-CoV-2 in a clinical specimen (Supplementary File 1 online). A multipronged infection control strategy was implemented to prevent nosocomial transmission of SARS-CoV-2. In addition to the enforcement of hand hygiene and environmental cleaning, it included the following specific components: (1) stepwise enhancement of laboratory surveillance for early isolation of COVID-19 patients in AIIRs; (2) proactive screening for high-risk groups in the quarantine camp; (3) daily monitoring of the utilization of AIIRs; (4) temporary test centers, as well as the CIF and CTF, to relieve overcrowding in hospitals; (5) universal masking for HCWs and patients; (6) directly observed donning and doffing among HCWs; (7) prudent use of PPE in performing aerosol-generating procedures (AGPs); (8) special dinning arrangements for HCWs in hospitals; (9) fewer visitors in hospitals; and (10) just-in-time infection control education to the HCWs, including simulation training.

Simulation methodology was adopted for practices and drills to control the spread of SARS-CoV-2. The simulation training raised HCW awareness of the importance of building the competency of their entire team with better handling of COVID-19 patients. The training focused on the performance of high-risk procedures such as resuscitation and transportation of COVID-19 patients. Each 3hour training session included a 45-minute lecture, scenario-based simulation in practice, and a debriefing session.

When COVID-19 patients were diagnosed in the non-AIIRs in hospitals, an infection control team performed an outbreak investigation and contact tracing for HCWs and hospitalized patients who met the criteria of close contact. For HCWs, a close contact was defined as one who carried out AGPs for the confirmed case without wearing appropriate PPE including surgical respirator, cap, face shield, isolation gown, and gloves. For patients, a close contact was defined as having face-to-face contact for >15 minutes or staying in the same cubicle for >2 hours with the confirmed case, regardless of whether surgical masks were worn.

Soon after the first imported case of COVID-19 was officially reported on January 23, 2020 (day 24), an electronic system of notification of infectious disease was activated for HCWs to report their illnesses, such as fever with or without any respiratory symptoms. A diagnostic test for SARS-CoV-2 by RT-PCR was offered to any symptomatic HCWs and to anyone classified as close contact with a confirmed case. Repeated testing was performed according to clinical assessment if the result of the first RT-PCR was negative for SARS-CoV-2. SARS-CoV-2 testing was also offered if a confirmed community case was living in the same residential building as our HCWs. For HCWs confirmed with COVID-19, epidemiological investigation was conducted by the infection control team to determine whether the HCW cases were hospital-acquired COVID-19 (HAC) or community-acquired COVID-19 (CAC). HAC was reported if the HCW had inappropriate PPE or any lapse in infection control procedures when caring for a confirmed case in the 14 days prior to symptom onset. Undetermined status was reported if the HCW had cared for COVID-19 cases with appropriate PPE in the 14 days prior to symptom onset and had no known source of infection in the community. CAC was reported if the HCW had a history of travel to areas with community transmission of COVID-19 or if the HCW was exposed to a person with COVID-19, such as household members of a family with a COVID-19 case, or if the HCW had had contact with staff confirmed with COVID-19 in the nonclinical setting and without appropriate PPE during patient care in the 14 days prior to symptom onset. The incidence of HCW infection per 1,000 full-time equivalent (FTE) among professional staff (ie, doctors, nurses, and allied health staff) and nonprofessional staff in the hospitals was analyzed. The FTEs of professional and nonprofessional staff were obtained from the Hospital Authority Annual Report 2019-2020. 11

The χ 2 exact test was used to compare independent categorical variables between groups. A P value of <.05 was considered statistically significant.

Of 5,296 COVID-19 patients, 4,808 (90.8%) were diagnosed in the first wave (142 cases), the second wave (896 cases), and the third wave (3,770 cases), with an overall incidence of 0.71 per 1,000 population in the first 300 days in Hong Kong ( Supplementary Fig. 1  online) . 12, 13 The median age was 43 years (range, 1 month-100 years) and 2,665 (50.3%) were female. With the exception of 1 patient who died before admission, all patients confirmed with COVID-19 were admitted to our public healthcare system. The median length of stay was 13 days (range, 1-128), with a total of 78,834 COVID-19 patient days.

Learning from the previous SARS epidemic, protecting HCWs from COVID-19 was the consensus priority in our healthcare settings from the date when the outbreak of community-acquired pneumonia in Wuhan, Hubei Province was announced (December 31, 2019). 14 With the implementation of a multipronged infection control strategy, we extended our infection control preparedness beyond the hospitals for early recognition and isolation of COVID-19 patients in Hong Kong. In the community, a quarantine center was set up for the close contacts of confirmed cases or returning travelers from high-risk regions or countries.

A team of hospital staff composed of infection control professionals, nurses, and phlebotomists attended the quarantine center to collect nasopharyngeal swabs serially for early diagnosis of COVID-19 among 469 Hong Kong residents being evacuated from Hubei province, China, by 4 charter flights on days 65 and 66. 15 A temporary test center was also set up at the Hong Kong International Airport for rapid diagnosis of COVID-19 among inbound travelers. 16 In the hospitals, active surveillance evolved from testing patients with clinical and epidemiological characteristics of COVID-19 initially to universal admission screening on day 254. In total, 8 tiers of enhanced laboratory surveillance were performed step by step (Table 1) . A cumulative number of 1.3 million specimens for SARS-CoV-2 were tested using RT-PCR from January to October 2020 in the public healthcare setting in Hong Kong, with an average of 3,600 specimens tested per month ( Fig. 1 ) and an average of 250 test performed per confirmed COVID-19 case.

As the COVID-19 patients were isolated in AIIRs, the utilization of AIIR beds and rooms in the hospitals was monitored daily from the second wave onward (Fig. 2) . The CIF and CTF were activated from July 24, 2020 (day 207) to September 18, 2020 (day 263), 10 with 918 patients diverting to the CIF (243 patients) and CTF (675 patients) respectively, which admitted 918 (33.4%) of 2,747 COVID-19 patients during that period. We adopted contact, droplet, and airborne precautions to care for the suspected and confirmed COVID-19 patients in the AIIRs with appropriate PPE, which included surgical respirator, cap, face shield, isolation gown, and gloves, as previously described. 17 Directly observed donning and doffing with a buddy system among HCWs was introduced in the hospitals, the CIF, and the CTF, in addition to standard infection control training. 10, 16 The infection control team demonstrated and audited the appropriate use of PPE. Prudent use of PPE during AGPs was promoted to extend the use of N95 surgical respirators and face shields during serial patient encounters unless the N95 surgical respirator or face shield was damaged or soiled. 18, 19 Hand hygiene was enforced, and staff also changed their gloves and gowns between patients. Subsequently, an alternative source of surgical respirator (a locally manufactured surgical respirator that was a European conformity certified nanofiber bactericidal surgical personal protective device) was introduced to relieve the shortage of N95 surgical respirators.

Universal masking was adopted, and the compliance of wearing surgical mask among HCWs was reported to be 100% in the clinical areas. 20 Infection control measures were enforced for HCWs during activities without masks, such as meals. In the hospital canteen and pantry, chairs and tables were arranged in a unidirectional setting with partitions separating the tables and at least 1 m apart. Alcohol-based hand rub and disinfectant wipes were provided for staff use in the dining areas in the hospitals. Talking and interaction without surgical masks among HCWs were discouraged. Visitation to hospitalized patients was not allowed except for compassionate reasons, such as for terminally ill or peripartum patients, to reduce the risk of COVID-19 transmission from the community. A regular staff forum was held, and infection control teaching material with 52 updates were uploaded to the Hospital Authority website in the first 300 days of the COVID-19 pandemic.

During the initial phase of the COVID-19 outbreak, 5 sessions of simulation training "train-the-trainer (TTT) phase" were organized at a designated training center on January 24, 2020 (day 25), day 30, day 31, day 32, and February 13, 2020 (day 45). In total, 117 HCW participants from 7 hospital networks joined the TTT phase from medicine (26%), intensive care unit (23%), accidental

in the public healthcare seƫng in Hong Kong (from January to October 2020)

Average number of specimens tested for SARS-CoV-2 per day Total number of specimens tested for SARS-CoV-2 per month The epidemiological investigation was reported previously. 39 i Of 9 close contacts, there were 2 secondary cases. The first was a 77-year-old female patient diagnosed with COVID-19 on July 13, 2020. As this patient was transferred to another cubicle, another 5 patients were classified as close contacts. Another was a 64-year-old female patient who was diagnosed on July 14, 2020. 

Furthermore, 5 cases of nosocomial transmission of COVID-19 originated from 20 patients with initially unrecognized COVID-19 status. Of 272 patients classified as close contacts, 8 (2.9%) had COVID-19. Of 41 HCWs classified as close contacts, none acquired COVID-19, which was confirmed by negative testing throughout the quarantine period.

During the first 300 days of the COVID-19 pandemic, 446 HCWs reported sick to the electronic system of notification of infectious disease, and 38 HCWs had COVID-19 (Fig. 3) . The incidence of COVID-19 among HCWs was significantly lower than that of general population in Hong Kong (0.46 per 1,000 HCWs vs 0.71 per 1,000 population; P = .008). Of 38 HCWs, 5 (13.2%) were asymptomatic (9 men and 29 women). The median age was 42 years (range, . With the exception of 1 nurse with undetermined COVID-19 acquisition, and 5 nonprofessional staff acquired the infection from nonclinical settings (office, dinning place, and dormitory room), another 32 HCWs acquired COVID-19 from the community. None of the HCWs had documented transmission of SARS-CoV-2 from COVID-19 patients in the clinical setting, despite 78,834 COVID-19 patient days. Of the 38 infected HCWs, 13 were professional staff (2 doctors, 11 nurses) and 25 were nonprofessional staff (2 cleaning, 8 clerical, 4 patient care assistant, 10 supporting, and 1 security staff) ( Table 3 ). The incidence of COVID-19 among professional staff was 0.30 per 1,000 FTE, which was significantly lower than that of nonprofessional staff (0.66 per 1,000 FTE; P = .022). Also, 34 HCWs were infected with SARS-CoV-2 in the third wave. The number of infected HCWs per 1,000 FTE was significantly higher in the third wave than in the first and second waves combined (0.41 vs 0.05; P < .001). In total, 112 HCWs were classified as close contacts of infected HCWs, with an average of 3 close contacts per index HCW, and 5 (4.5%) of these developed COVID-19 during the quarantine period.

With the increasing number of nosocomial transmissions and outbreaks of COVID-19, 21 our multipronged infection control strategy successfully prevented the nosocomial acquisition of SARS-CoV-2 among HCWs during patient care in the first 300 days of the COVID-19 pandemic in Hong Kong, despite 78,834 COVID-19 patient days. In our multipronged infection control strategy, we advocated liberal testing for early isolation of all suspected and confirmed cases in the public hospitals, 17 the CIF, and the CTF. 10 This strategy contrasts with the policies of many Western countries where SARS-CoV-2 testing may not be readily accessible and most COVID-19 patients with mild-to-moderate disease have been managed at home 22, 23 to protect the healthcare service from overloading and to reduce the risk of HCW infection due to fatigue with lapses in infection control procedures or depletion of PPE. Hong Kong did the exact opposite. Our hospital-based HCWs even proactively went to quarantine centers 15, 24 and airports 16 to collect specimens for testing with a short turnaround time of 4-8 hours to minimize community transmission. Paradoxically, our heavily hospital-based approach spared our healthcare service from being overloaded. Epidemiological investigation was performed to determine the exposure from household members, healthcare workers in hospitals, patients with retrospective diagnosis of COVID-19 in non-airborne infection isolation room, and caring confirmed COVID-19 patients in airborne infection isolation room in the previous 14 d. e As universal masking was implemented in the hospitals during COVID-19 pandemic, and appropriate personal protective equipment was worn during patient care procedure in the epidemiological investigation, no patient was defined as a close contact from the infected healthcare workers. Close contact among healthcare worker is defined as those who had face-to-face interaction without wearing surgical masks for >15 min such as dining inside or outside hospitals. During the quarantine period of 14 d, and followed by medical surveillance of another 14 d, there was no secondary case of COVID-19 among the close contacts. f Of 33 close contacts in the office, 2 clerical and 1 supporting staff (case nos. 9-11) were diagnosed to have COVID-19 during the quarantine period. g COVID-19 was diagnosed in the quarantine facility. When all of the confirmed COVID-19 patients were isolated, appropriate use of PPE became the most important parameter to prevent HCW infection, as illustrated in a recent analysis. 25 We adopted directly observed donning and doffing, a buddy system to enhance the compliance of appropriate use of PPE, especially when caring for a suspected or confirmed case of COVID-19, not only in hospitals but also in CIF and CTF. 10 The CIF and CTF diverted one-third of COVID-19 patients to relieve overcrowding in hospitals, which may have reduced the risk to HCWs. Universal masking was mandated in the hospitals, 20 associated with the enforcement of hand hygiene, 26 environmental hygiene, 27 and standard precautions during the COVID-19 pandemic. These measures may explain why none of 41 HCWs classified as close contacts after caring for unrecognized cases acquired COVID-19.

Infection control training is associated with decreased infection risk of COVID-19, 25 which markedly contributed to our zero nosocomial acquisition of SARS-CoV-2 among HCWs. In Hong Kong, infection control training has been regularly provided to HCWs working in the hospitals, the CIF, and the CTF, along with PPE training, especially for those caring for COVID-19 patients. 10, 17 Simulation training was organized with particular focus on infection control in the high-risk procedures, such as resuscitation and patient transfers, in the early phase of the COVID-19 pandemic. In fact, simulation training has been increasingly applied in different clinical specialties for COVID-19 prepardedness. 28, 29 Simulation exercises have proven to be an effective strategy to increase self-efficacy, to decrease anxiety for HCWs, and to build interprofessional teamwork in response to infectious diseases. 30 Stringent infection control measures protected HCWs from SARS-CoV-2 in the clinical setting, but HCWs may have acquired SARS-CoV-2 from a nonclinical source, similar to the Netherlands, where most infected HCWs acquired SARS-CoV-2 in the community. 31 However, our HCWs had a significantly lower incidence of COVID-19 than the general population, in contrast with reports that patient-facing HCWs had higher odds of a positive test 32 and a 3-fold increased risk of admission with COVID-19. 33 With our intense infection control training, our HCWs were more alert and vigilant in both hospital and community settings. However, the alertness of our nonprofessional staff was lower than that of the professional staff, resulting in HCW-to-HCW transmission in nonclinical settings when they were dining together or staying in the dormitory without masks. Activities without masks increased the risk of COVID-19 outbreaks. 34, 35 The short-range airborne route may dominate exposure to SARS-CoV-2 during close contact, 36 especially in poorly ventilated indoor or dining places. 37 Therefore, we enforced social distancing in the hospital canteen and pantry.

With the emergence of mutant strains of COVID-19 with higher transmissibility and antibody or vaccine resistance, 38 the risk of HCW infection will further increase. We will continue our multipronged infection control strategy to minimize the risk of nosocomial acquisition of SARS-CoV-2 among our HCWs.

World Health Organization website

Critical shortage or lack of personal protective equipment in the context of COVID-19. Western Pacific Region. World Health Organization website

Risk of COVID-19 among frontline healthcare workers and the general community: a prospective cohort study

Infection and mortality of healthcare workers worldwide from COVID-19: a systematic review

COVID-19 in healthcare workers: a living systematic review and meta-analysis of prevalence, risk factors, clinical characteristics, and outcomes

19-has-infected-some-570000-health-workers-andkilled-2500-americas-paho

Estimating coronavirus disease 2019 infection risk in healthcare workers

World Health Organization website

The Centre for Health Protection closely monitors cluster of pneumonia cases on Mainland. Department of Health, Hong Kong Special Administrative Region website

Infection control challenges in setting up community isolation and treatment facilities for patients with coronavirus disease 2019 (COVID-19): implementation of directly-observed environmental disinfection

Hong Kong Hospital Authority website

Centre for health protection. Hong Kong Hospital Authority coronavirus website

Unique SARS-CoV-2 clusters causing a large COVID-19 outbreak in Hong Kong

Absence of nosocomial transmission of coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 in the prepandemic phase in Hong Kong

Seroprevalence of SARS-CoV-2 in Hong Kong and in residents evacuated from Hubei province, China: a multicohort study

Infection control challenge in setting up a temporary test centre at Hong Kong International Airport for rapid diagnosis of COVID-19 due to SARS-CoV-2

Escalating infection control response to the rapidly evolving epidemiology of the coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 in Hong Kong

Recommended guidance for extended use and limited reuse of N95 filtering facepiece respirators in healthcare settings

Infectious Diseases Society of America Guidelines on infection prevention for health care personnel caring for patients with suspected or known COVID-19

Absence of nosocomial influenza and respiratory syncytial virus infection in the coronavirus disease 2019 (COVID-19) era: implication of universal masking in hospitals

Nosocomial transmission and outbreaks of coronavirus disease 2019: the need to protect both patients and healthcare workers

Interim clinical guidance for management of patients with confirmed coronavirus disease (COVID-19)

COVID-19 rapid guideline: managing symptoms (including at the end of life) in the community. National Institute for Health and Care Excellence website

SARS-CoV-2 shedding and seroconversion among passengers quarantined after disembarking a cruise ship: a case series

Epidemiology of and risk factors for coronavirus infection in healthcare workers: a living rapid review

Is it possible to achieve 100% hand hygiene compliance during the coronavirus disease 2019 (COVID-19) pandemic?

Air and environmental sampling for SARS-CoV-2 around hospitalized patients with coronavirus disease 2019 (COVID-19)

Rapid implementation of COVID-19 tracheostomy simulation training to increase surgeon safety and confidence

Use of simulation to develop a COVID-19 resuscitation process in a pediatric emergency department

High consequence infectious diseases training using interprofessional simulation and TeamSTEPPS

Prevalence and clinical presentation of health care workers with symptoms of coronavirus disease 2019 in 2 Dutch hospitals during an early phase of the pandemic

Impact of the COVID-19 pandemic on healthcare workers' risk of infection and outcomes in a large, integrated health system

Risk of hospital admission with coronavirus disease 2019 in healthcare workers and their households: nationwide linkage cohort study

The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2

Contact screening for healthcare workers exposed to patients with COVID-19

Multiroute respiratory infection: when a transmission route may dominate

COVID-19 outbreak associated with air conditioning in restaurant

Early transmissibility assessment of the N501Y mutant strains of SARS-CoV-2 in the United Kingdom

Risk of nosocomial transmission of coronavirus disease 2019: an experience in a general ward setting in Hong Kong

Acknowledgments. We thank all the frontline and management staff of Hospital Authority for supporting and adhering to the infection control measuresduring COVID-19 pandemic. We also thank the staff involved in the setting up and maintenance of the community isolation facility at Lei Yue Mun Park and HolidayVillage, and the community treatment facility at AsiaWord-Expo.