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1.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315187

ABSTRACT

The Covid-19 pandemic has focused attention on airborne transmission of viruses. Using realistic air flow simulation, we model droplet dispersion from coughing and study the transmission risk related to SARS-CoV-2. Although most airborne droplets are 8-16 $μ$m in diameter, the droplets with the highest transmission potential are, in fact, 32-40 $μ$m. Use of face masks is therefore recommended for both personal and social protection. We found social distancing effective at reducing transmission potential across all droplet sizes. However, the presence of a human body 1 m away modifies the aerodynamics so that downstream droplet dispersion is enhanced, which has implications on safe distancing in queues. Based on median viral load, we found that an average of 0.55 viral copies is inhaled at 1 m distance per cough. Droplet evaporation results in significant reduction in droplet counts, but airborne transmission remains possible even under low humidity conditions.

4.
Glob Chall ; 5(11): 2100030, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1335995

ABSTRACT

To curb the spread of the COVID-19 virus, the use of face masks such as disposable surgical masks and N95 respirators is being encouraged and even enforced in some countries. The widespread use of masks has resulted in global shortages and individuals are reusing them. This calls for proper disinfection of the masks while retaining their protective capability. In this study, the killing efficiency of ultraviolet-C (UV-C) irradiation, dry heat, and steam sterilization against bacteria (Staphylococcus aureus), fungi (Candida albicans), and nonpathogenic virus (Salmonella virus P22) is investigated. UV-C irradiation for 10 min in a commercial UV sterilizer effectively disinfects surgical masks. N95 respirators require dry heat at 100 °C for hours while steam treatment works within 5 min. To address the question on safe reuse of the disinfected masks, their bacteria filtration efficiency, particle filtration efficiency, breathability, and fluid resistance are assessed. These performance factors are unaffected after 5 cycles of steam (10 min per cycle) and 10 cycles of dry heat at 100 °C (40 min per cycle) for N95 respirators, and 10 cycles of UV-C irradiation for surgical masks (10 min per side per cycle). These findings provide insights into formulating the standard procedures for reusing masks without compromising their protective ability.

5.
Singapore Med J ; 2021 Jun 22.
Article in English | MEDLINE | ID: covidwho-1280945

ABSTRACT

INTRODUCTION: Healthcare workers (HCWs) are a critical resource in the effort to control the COVID-19 pandemic. They are also a sentinel surveillance population whose clinical status reflects the effectiveness of the hospital's infection prevention measures in the pandemic. METHODS: This was a retrospective cohort study conducted in Singapore General Hospital (SGH), a 1,822-bed tertiary hospital. Participants were all HCWs working in SGH during the study period. HCW protection measures included clinical workflows and personal protective equipment developed and adapted to minimise the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. HCW monitoring comprised staff contact logs in high-risk locations, twice-daily temperature monitoring, assessment of HCWs with acute respiratory illnesses (ARIs) in the staff clinic and, in the event of an exposure, extensive contact tracing, detailed risk assessment and risk-based interventions. HCW surveillance utilised monitoring data and ARI presentations and outcomes. RESULTS: In the ten-week period between 6 January 2020 and 16 March 2020, 333 (17.1%) of 1,946 HCWs at risk of occupational COVID-19 presented with ARI. 32 (9.6%) screened negative for SARS-CoV-2 from throat swabs. Five other HCWs developed COVID-19 attributed to non-clinical exposures. From the nine COVID-19 exposure episodes investigated, 189 HCW contacts were identified, of whom 68 (36.2%) were placed on quarantine and remained well. CONCLUSION: Early in an emerging infectious disease outbreak, close monitoring of frontline HCWs is essential in ascertaining the effectiveness of infection prevention measures. HCWs are at risk of community disease acquisition and should be monitored and managed to prevent onward transmission.

6.
Sci Rep ; 11(1): 4617, 2021 02 25.
Article in English | MEDLINE | ID: covidwho-1104549

ABSTRACT

The Covid-19 pandemic has focused attention on airborne transmission of viruses. Using realistic air flow simulation, we model droplet dispersion from coughing and study the transmission risk related to SARS-CoV-2. Although this model defines most airborne droplets as 8-16 µm in diameter, we infer that larger droplets of 32-40 µm in diameter may potentially be more infectious due to higher viral content. Use of face masks is therefore recommended for both personal and social protection. We found social distancing effective at reducing transmission potential across all droplet sizes. However, the presence of a human body 1 m away modifies the aerodynamics so that downstream droplet dispersion is enhanced, which has implications on safe distancing in queues. At 1 m distance, we found that an average of 0.55 viral copies is inhaled for a cough at median loading, scalable up to 340 copies at peak loading. Droplet evaporation results in significant reduction in droplet counts, but airborne transmission remains possible even under low humidity conditions.


Subject(s)
Air Microbiology , COVID-19/transmission , Cough/virology , SARS-CoV-2/physiology , Humans , Hydrodynamics , Masks , Models, Biological , Particle Size , Risk Assessment
7.
Ann Transplant ; 25: e926992, 2020 Dec 08.
Article in English | MEDLINE | ID: covidwho-1000626

ABSTRACT

BACKGROUND In solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients, coronavirus disease 2019 (COVID-19) can contribute to a severe clinical course and an increased risk of death. Thus, patients awaiting a SOT or HSCT face the dilemma of choosing between a life-saving treatment that presents a significant threat of COVID-19 and the risk of waitlist dropout, progression of disease, or mortality. The lack of established literature on COVID-19 complicates the issue as patients, particularly those with inadequate health literacy, may not have the resources needed to navigate these decisions. MATERIAL AND METHODS We conducted a standardized phone survey of patients awaiting SOT or HSCT to assess the prevalence of inadequate health literacy and attitudes toward transplant during the COVID-19 pandemic. RESULTS Seventy-one patients completed the survey, with a response rate of 84.5%. Regardless of health literacy, most waitlisted candidates recognized that the current pandemic is a serious situation affecting their care and that COVID-19 poses a significant risk to their health. Despite the increased risks, most patients reported they would choose immediate transplantation if there was no foreseeable end to the pandemic, and especially if the medical urgency did not permit further delay. There were no differences in responses across the patient waitlist groups for heart, kidney, liver, and stem cell transplant. CONCLUSIONS These findings can help transplant centers decide how transplantation services should proceed during this pandemic and can be used to educate patients and guide discussions about informed consent for transplant during the COVID-19 pandemic.


Subject(s)
COVID-19/psychology , Health Knowledge, Attitudes, Practice , Hematopoietic Stem Cell Transplantation/psychology , Organ Transplantation/psychology , Patient Preference/psychology , Waiting Lists , Adult , Aged , Aged, 80 and over , COVID-19/epidemiology , COVID-19/etiology , COVID-19/prevention & control , Female , Global Health , Health Care Surveys , Health Literacy , Humans , Male , Middle Aged , Pandemics , Patient Preference/statistics & numerical data , Postoperative Complications/prevention & control , Postoperative Complications/psychology , Singapore/epidemiology
8.
AJR Am J Roentgenol ; 214(6): 1206-1210, 2020 06.
Article in English | MEDLINE | ID: covidwho-823643

ABSTRACT

OBJECTIVE. This article shares the ground operational perspective of how a tertiary hospital radiology department in Singapore is responding to the coronavirus disease (COVID-19) epidemic. This same department was also deeply impacted by the severe acute respiratory syndrome (SARS) outbreak in 2003. CONCLUSION. Though similar to SARS, the COVID-19 outbreak has several differences. We share how lessons from 2003 are applied and modified in our ongoing operational response to this evolving novel pathogen.


Subject(s)
Coronavirus Infections/epidemiology , Coronavirus Infections/prevention & control , Epidemics , Infection Control/standards , Pandemics/prevention & control , Pneumonia, Viral/epidemiology , Pneumonia, Viral/prevention & control , Radiology Department, Hospital/organization & administration , Radiology Department, Hospital/standards , Severe Acute Respiratory Syndrome/epidemiology , Severe Acute Respiratory Syndrome/prevention & control , COVID-19 , Humans , Singapore/epidemiology
9.
ACS Mater Lett ; 2: 1178-1181, 2020.
Article in English | MEDLINE | ID: covidwho-834849

ABSTRACT

A smart mask integrated with a remote, noncontact multiplexed sensor system, or "Lab-on-Mask" (LOM) is designed for monitoring respiratory diseases, such as the COVID-19. This LOM can monitor the heart rate, blood oxygen saturation, blood pressure, and body temperature associated with symptoms of pneumonia caused by coronaviruses in real time. Because of this remote monitoring system, frontline healthcare staff can minimize the exposure they face from close contact with the patients and reduce the risks of being infected.

10.
Research (Wash D C) ; 2020: 7286735, 2020.
Article in English | MEDLINE | ID: covidwho-729852

ABSTRACT

The increasing prevalence of infectious diseases in recent decades has posed a serious threat to public health. Routes of transmission differ, but the respiratory droplet or airborne route has the greatest potential to disrupt social intercourse, while being amenable to prevention by the humble face mask. Different types of masks give different levels of protection to the user. The ongoing COVID-19 pandemic has even resulted in a global shortage of face masks and the raw materials that go into them, driving individuals to self-produce masks from household items. At the same time, research has been accelerated towards improving the quality and performance of face masks, e.g., by introducing properties such as antimicrobial activity and superhydrophobicity. This review will cover mask-wearing from the public health perspective, the technical details of commercial and home-made masks, and recent advances in mask engineering, disinfection, and materials and discuss the sustainability of mask-wearing and mask production into the future.

11.
Surg Infect (Larchmt) ; 21(9): 760-765, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-680792

ABSTRACT

Background: In the ongoing coronavirus disease 2019 (COVID-19) pandemic, resuming provision of surgical services poses a challenge given that patients may have acute surgical pathologies with concurrent COVID-19 infection. We utilized a risk-stratified approach to allow for early recognition and isolation of potential COVID-19 infection in surgical patients, ensuring continuity of surgical services during a COVID-19 outbreak. Patients and Methods: Over a four-month period from January to April 2020, surgical patients admitted with concurrent respiratory symptom, infiltrates on chest imaging, or suspicious travel/epidemiologic history were placed in a dedicated ward in which they were tested for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). If emergency operations were necessary prior to the exclusion of COVID-19, patients were managed as per suspected cases of COVID-19, with appropriate precautions and full personal protective equipment (PPE). Results: From January through April 2020, a total of 8,437 patients were admitted to our surgical department; 5.9% (498/8437) required peri-operative testing for SARS-CoV-2. Because testing was in-house with turnaround within 24 hours, only a small number of emergency operations (n = 10) were conducted for suspected COVID-19 cases prior to results; none tested positive. The testing yield was lower in surgical inpatients compared with medical inpatients (odds ratio [OR] = 0.20, 95% confidence interval [CI], 0.12-0.32, p < 0.001). Three operations were conducted in known COVID-19 cases; all healthcare workers (HCWs) used full PPE. A risk-stratified testing strategy picked up previously unsuspected COVID-19 in six cases; 66.7% (4/6) were asymptomatic at presentation. Although 48 HCWs were exposed to these six cases, delayed diagnosis was averted and no evidence of spread to patients or HCWs was detected. Conclusion: A risk-stratified approach allowed for early recognition, testing, and isolation of potential COVID-19 infection in surgical patients, ensuring continuity of surgical services.


Subject(s)
Coronavirus Infections/diagnosis , Coronavirus Infections/physiopathology , Inpatients , Patient Isolation/methods , Pneumonia, Viral/diagnosis , Pneumonia, Viral/physiopathology , Adult , COVID-19 , Disease Outbreaks , Female , Humans , Male , Middle Aged , Pandemics , Personal Protective Equipment , Risk Assessment , Singapore , Surgical Procedures, Operative , Tertiary Care Centers
12.
Infect Control Hosp Epidemiol ; 41(7): 765-771, 2020 07.
Article in English | MEDLINE | ID: covidwho-622776

ABSTRACT

OBJECTIVE: Staff surveillance is crucial during the containment phase of a pandemic to help reduce potential healthcare-associated transmission and sustain good staff morale. During an outbreak of SARS-COV-2 with community transmission, our institution used an integrated strategy for early detection and containment of COVID-19 cases among healthcare workers (HCWs). METHODS: Our strategy comprised 3 key components: (1) enforcing reporting of HCWs with acute respiratory illness (ARI) to our institution's staff clinic for monitoring; (2) conducting ongoing syndromic surveillance to obtain early warning of potential clusters of COVID-19; and (3) outbreak investigation and management. RESULTS: Over a 16-week surveillance period, we detected 14 cases of COVID-19 among HCWs with ARI symptoms. Two of the cases were linked epidemiologically and thus constituted a COVID-19 cluster with intrahospital HCW-HCW transmission; we also detected 1 family cluster and 2 clusters among HCWs who shared accommodation. No transmission to HCWs or patients was detected after containment measures were instituted. Early detection minimized the number of HCWs requiring quarantine, hence preserving continuity of service during an ongoing pandemic. CONCLUSIONS: An integrated surveillance strategy, outbreak management, and encouraging individual responsibility were successful in early detection of clusters of COVID-19 among HCWs. With ongoing local transmission, vigilance must be maintained for intrahospital spread in nonclinical areas where social mingling of HCWs occurs. Because most individuals with COVID-19 have mild symptoms, addressing presenteeism is crucial to minimize potential staff and patient exposure.


Subject(s)
Coronavirus Infections/diagnosis , Coronavirus Infections/prevention & control , Infection Control/methods , Pandemics/prevention & control , Personnel, Hospital , Pneumonia, Viral/diagnosis , Pneumonia, Viral/prevention & control , Population Surveillance , Adult , COVID-19 , Cluster Analysis , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Early Diagnosis , Female , Hospitals, General , Humans , Male , Middle Aged , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Singapore/epidemiology , Symptom Assessment , Young Adult
13.
Am J Infect Control ; 48(9): 1056-1061, 2020 09.
Article in English | MEDLINE | ID: covidwho-619967

ABSTRACT

BACKGROUND: During an ongoing outbreak of COVID-19, unsuspected cases may be housed outside of dedicated isolation wards. AIM: At a Singaporean tertiary hospital, individuals with clinical syndromes compatible with COVID-19 but no epidemiologic risk were placed in cohorted general wards for COVID-19 testing. To mitigate risk, an infection control bundle was implemented comprising infrastructural enhancements, improved personal protective equipment, and social distancing. We assessed the impact on environmental contamination and transmission. METHODS: Upon detection of a case of COVID-19 in the dedicated general ward, patients and health care workers (HCWs) contacts were identified. All patient and staff close-contacts were placed on 14-day phone surveillance and followed up for 28 days; symptomatic contacts were tested. Environmental samples were also obtained. FINDINGS: Over a 3-month period, 28 unsuspected cases of COVID-19 were contained in the dedicated general ward. In 5 of the 28 cases, sampling of the patient's environment yielded SARS-CoV-2; index cases who required supplemental oxygen had higher odds of environmental contamination (P = .01). A total of 253 staff close-contacts and 45 patient close-contacts were identified; only 3 HCWs (1.2%, 3/253) required quarantine. On 28-day follow-up, no patient-to-HCW transmission was documented; only 1 symptomatic patient close-contact tested positive. CONCLUSIONS: Our institution successfully implemented an intervention bundle to mitigate COVID-19 transmission in a multibedded cohorted general ward setting.


Subject(s)
Coronavirus Infections/transmission , Cross Infection/prevention & control , Disease Transmission, Infectious/prevention & control , Patients' Rooms , Pneumonia, Viral/transmission , Quarantine/methods , Adult , Aged , Betacoronavirus , COVID-19 , Contact Tracing , Coronavirus Infections/prevention & control , Female , Humans , Male , Middle Aged , Pandemics/prevention & control , Patient Care Bundles , Patient Isolation , Personal Protective Equipment , Pneumonia, Viral/prevention & control , SARS-CoV-2 , Singapore/epidemiology
15.
Transplant Direct ; 6(6): e554, 2020 Jun.
Article in English | MEDLINE | ID: covidwho-208897

ABSTRACT

The current coronavirus disease 2019 (COVID-19) pandemic has not only caused global social disruptions but has also put tremendous strain on healthcare systems worldwide. With all attention and significant effort diverted to containing and managing the COVID-19 outbreak (and understandably so), essential medical services such as transplant services are likely to be affected. Closure of transplant programs in an outbreak caused by a highly transmissible novel pathogen may be inevitable owing to patient safety. Yet program closure is not without harm; patients on the transplant waitlist may die before the program reopens. By adopting a tiered approach based on outbreak disease alert levels, and having hospital guidelines based on the best available evidence, life-saving transplants can still be safely performed. We performed a lung transplant and a liver transplant successfully during the COVID-19 era. We present our guidelines and experience on managing the transplant service as well as the selection and management of donors and recipients. We also discuss clinical dilemmas in the management COVID-19 in the posttransplant recipient.

16.
Infect Control Hosp Epidemiol ; 41(7): 820-825, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-196681

ABSTRACT

OBJECTIVES: Patients with COVID-19 may present with respiratory syndromes indistinguishable from those caused by common viruses. Early isolation and containment is challenging. Although screening all patients with respiratory symptoms for COVID-19 has been recommended, the practicality of such an effort has yet to be assessed. METHODS: Over a 6-week period during a SARS-CoV-2 outbreak, our institution introduced a "respiratory surveillance ward" (RSW) to segregate all patients with respiratory symptoms in designated areas, where appropriate personal protective equipment (PPE) could be utilized until SARS-CoV-2 testing was done. Patients could be transferred when SARS-CoV-2 tests were negative on 2 consecutive occasions, 24 hours apart. RESULTS: Over the study period, 1,178 patients were admitted to the RSWs. The mean length-of-stay (LOS) was 1.89 days (SD, 1.23). Among confirmed cases of pneumonia admitted to the RSW, 5 of 310 patients (1.61%) tested positive for SARS-CoV-2. This finding was comparable to the pickup rate from our isolation ward. In total, 126 HCWs were potentially exposed to these cases; however, only 3 (2.38%) required quarantine because most used appropriate PPE. In addition, 13 inpatients overlapped with the index cases during their stay in the RSW; of these 13 exposed inpatients, 1 patient subsequently developed COVID-19 after exposure. No patient-HCW transmission was detected despite intensive surveillance. CONCLUSIONS: Our institution successfully utilized the strategy of an RSW over a 6-week period to contain a cluster of COVID-19 cases and to prevent patient-HCW transmission. However, this method was resource-intensive in terms of testing and bed capacity.


Subject(s)
Coronavirus Infections/transmission , Cross Infection/transmission , Infection Control/methods , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Occupational Diseases/prevention & control , Patient Isolation , Pneumonia, Viral/transmission , Population Surveillance/methods , Adult , Aged , Aged, 80 and over , Betacoronavirus , COVID-19 , Coronavirus Infections/diagnosis , Coronavirus Infections/prevention & control , Cross Infection/diagnosis , Cross Infection/prevention & control , Early Diagnosis , Female , Humans , Length of Stay , Male , Middle Aged , Pandemics/prevention & control , Patients' Rooms/organization & administration , Personal Protective Equipment , Pneumonia/virology , Pneumonia, Viral/diagnosis , Pneumonia, Viral/prevention & control , SARS-CoV-2 , Singapore , Symptom Assessment , Tertiary Care Centers
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