Transmission and Control of SARS

Evidence-based review of safe theatre practice during the COVID-19 pandemic beyond personal protective equipment

INTRODUCTION

COVID-19 remains a threat for a fear of a second pandemic. Emergency orthopaedic operations are still among the most commonly performed procedures with increased risk of transmission of SARS CoV-2 to the patients and the healthcare workers. The aim of this study was to present the evidence available into best practices limiting the spread of COVID-19 in healthcare setting during current and future pandemics.

METHODS

A review of the literature was performed in multiple databases (PubMed, the Cochrane Library, Google Scholar, World Health Organization and Centers for Disease Control), using 'COVID-19' with other relevant keywords in different combinations. Owing to the limited and heterogenous evidence available, data were presented in a narrative manner.

FINDINGS

From the evidence gathered it was noted that a multimodal approach to minimising pathogen transmission is required. This primarily comprises the wider engineering and administrative controls to reduce the concentration of the pathogen and to separate staff and patients from it. Theatre isolation and traffic control bundling, theatre flow and logistics, ventilation and waste management form a pivotal role in the environmental/engineering controls. Administrative measures include policies for both patients and staff. For patients, isolation and preoperative screening are of utmost value. For staff, testing for COVID-19, risk assessment, redeployment and provision of persona; protective equipment, together with the necessary training are important administrative controls.

CONCLUSION

We believe these measures are likely to improve the sustainability of resources and can be carried to elective settings in order to return to some form of normality and help to mitigate the effects of future pandemics.

Pathogenesis-directed therapy of 2019 novel coronavirus disease

The 2019 novel coronavirus disease (COVID-19) now is considered a global public health emergency. One of the unprecedented challenges is defining the optimal therapy for those patients with severe pneumonia and systemic manifestations of COVID-19. The optimal therapy should be largely based on the pathogenesis of infections caused by this novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the onset of COVID-19, there have been many prepublications and publications reviewing the therapy of COVID-19 as well as many prepublications and publications reviewing the pathogenesis of SARS-CoV-2. However, there have been no comprehensive reviews that link COVID-19 therapies to the pathogenic mechanisms of SARS-CoV-2. To link COVID-19 therapies to pathogenic mechanisms of SARS-CoV-2, we performed a comprehensive search through MEDLINE, PubMed, medRxiv, EMBASE, Scopus, Google Scholar, and Web of Science using the following keywords: COVID-19, SARS-CoV-2, novel 2019 coronavirus, pathology, pathologic, pathogenesis, pathophysiology, coronavirus pneumonia, coronavirus infection, coronavirus pulmonary infection, coronavirus cardiovascular infection, coronavirus gastroenteritis, coronavirus autopsy findings, viral sepsis, endotheliitis, thrombosis, coagulation abnormalities, immunology, humeral immunity, cellular immunity, inflammation, cytokine storm, superantigen, therapy, treatment, therapeutics, immune-based therapeutics, antiviral agents, respiratory therapy, oxygen therapy, anticoagulation therapy, adjuvant therapy, and preventative therapy. Opinions expressed in this review also are based on personal experience as clinicians, authors, peer reviewers, and editors. This narrative review linking COVID-19 therapies with pathogenic mechanisms of SARS-CoV-2 has resulted in six major therapeutic goals for COVID-19 therapy based on the pathogenic mechanisms of SARS-CoV-2. These goals are listed below: 1. The first goal is identifying COVID-19 patients that require both testing and therapy. This is best accomplished with a COVID-19 molecular test from symptomatic patients as well as determining the oxygen saturation in such patients with a pulse oximeter. Whether a symptomatic respiratory illness is COVID-19, influenza, or another respiratory pathogen, an oxygen saturation less than 90% means that the patient requires medical assistance. 2. The second goal is to correct the hypoxia. This goal generally requires hospitalization for oxygen therapy; other respiratory-directed therapies such as prone positioning or mechanical ventilation are often used in the attempt to correct hypoxemia due to COVID-19. 3. The third goal is to reduce the viral load of SARS-CoV-2. Ideally, there would be an oral antiviral agent available such as seen with the use of oseltamivir phosphate for influenza. This oral antiviral agent should be taken early in the course of SARS-CoV-2 infection. Such an oral agent is not available yet. Currently, two options are available for reducing the viral load of SARS-CoV-2. These are post-Covid-19 plasma with a high neutralizing antibody titer against SARS-CoV-2 or intravenous remdesivir; both options require hospitalization. 4. The fourth goal is to identify and address the hyperinflammation phase often seen in hospitalized COVID-19 patients. Currently, fever with an elevated C-reactive protein is useful for diagnosing this hyperinflammation syndrome. Low-dose dexamethasone therapy currently is the best therapeutic approach. 5. The fifth goal is to identify and address the hypercoagulability phase seen in many hospitalized COVID-19 patients. Patients who would benefit from anticoagulation therapy can be identified by a marked increase in d-dimer and prothrombin time with a decrease in fibrinogen. To correct this disseminated intravascular coagulation-like phase, anticoagulation therapy with low molecular weight heparin is preferred. Anticoagulation therapy with unfractionated heparin is preferred in COVID-19 patients with acute kidney injuries. 6. The last goal is prophylaxis for persons who are not yet infected. Potential supplements include vitamin D and zinc. Although the data for such supplements is not extremely strong, it can be argued that almost 50% of the population worldwide has a vitamin D deficiency. Correcting this deficiency would be beneficial regardless of any impact of COVID-19. Similarly, zinc is an important supplement that is important in one's diet regardless of any effect on SARS-CoV-2. As emerging therapies are found to be more effective against the SARS-CoV-2 pathogenic mechanisms identified, they can be substituted for those therapies presented in this review.

Preparing for a COVID-19 pandemic: a review of operating room outbreak response measures in a large tertiary hospital in Singapore

The coronavirus disease 2019 (COVID-19) outbreak has been designated a public health emergency of international concern. To prepare for a pandemic, hospitals need a strategy to manage their space, staff, and supplies so that optimum care is provided to patients. In addition, infection prevention measures need to be implemented to reduce in-hospital transmission. In the operating room, these preparations involve multiple stakeholders and can present a significant challenge. Here, we describe the outbreak response measures of the anesthetic department staffing the largest (1,700-bed) academic tertiary level acute care hospital in Singapore (Singapore General Hospital) and a smaller regional hospital (Sengkang General Hospital). These include engineering controls such as identification and preparation of an isolation operating room, administrative measures such as modification of workflow and processes, introduction of personal protective equipment for staff, and formulation of clinical guidelines for anesthetic management. Simulation was valuable in evaluating the feasibility of new operating room set-ups or workflow. We also discuss how the hierarchy of controls can be used as a framework to plan the necessary measures during each phase of a pandemic, and review the evidence for the measures taken. These containment measures are necessary to optimize the quality of care provided to COVID-19 patients and to reduce the risk of viral transmission to other patients or healthcare workers.

Modified gloves: A chance for the prevention of nosocomial infections

BACKGROUND

Non-sterile gloves primarily serve as a barrier protection for health care workers (HCWs). However, pathogens may often contaminate the skin of HCWs during glove removal; therefore, pathogens may be further transmitted and cause nosocomial infections.

METHODS

A field study was conducted comparing contamination rates when using standard gloves or a new modified product equipped with an additional flap (doffing aid) for easier removal. Gloves were removed after bathing gloved hands in an artificial fluorescent lotion. The number of contamination spots was then visually examined using ultraviolet light.

RESULTS

There were 317 individuals who participated in this study: 146 participants (104 nurses and 42 physicians) used standard gloves, whereas 171 participants (118 nurses and 53 physicians) used the modified product. Use of the modified gloves instead of the standard product (15.8% vs 73.3%, respectively; P < .001) and being a physician rather than a nurse (29.5% vs 47.7%, respectively; P = .003) were the only independent risk factors for reduction of contamination.

CONCLUSIONS

This study shows that the modified product could, at least in vitro, significantly reduce the rate of hand and wrist contamination during removal compared with standard gloves. By this, it may significantly improve the overall quality of patient care when used on the wards directly at the patient's site.

Transmission routes of respiratory viruses among humans

Respiratory tract infections can be caused by a wide variety of viruses. Airborne transmission via droplets and aerosols enables some of these viruses to spread efficiently among humans, causing outbreaks that are difficult to control. Many outbreaks have been investigated retrospectively to study the possible routes of inter-human virus transmission. The results of these studies are often inconclusive and at the same time data from controlled experiments is sparse. Therefore, fundamental knowledge on transmission routes that could be used to improve intervention strategies is still missing. We here present an overview of the available data from experimental and observational studies on the transmission routes of respiratory viruses between humans, identify knowledge gaps, and discuss how the available knowledge is currently implemented in isolation guidelines in health care settings.

Animal models in virus research: their utility and limitations

Viral diseases are important threats to public health worldwide. With the number of emerging viral diseases increasing the last decades, there is a growing need for appropriate animal models for virus studies. The relevance of animal models can be limited in terms of mimicking human pathophysiology. In this review, we discuss the utility of animal models for studies of influenza A viruses, HIV and SARS-CoV in light of viral emergence, assessment of infection and transmission risks, and regulatory decision making. We address their relevance and limitations. The susceptibility, immune responses, pathogenesis, and pharmacokinetics may differ between the various animal models. These complexities may thwart translating results from animal experiments to the humans. Within these constraints, animal models are very informative for studying virus immunopathology and transmission modes and for translation of virus research into clinical benefit. Insight in the limitations of the various models may facilitate further improvements of the models.

Comparison of hand contamination rates and environmental contamination levels between two different glove removal methods and distances

BACKGROUND

Gloves are a necessary contact precaution to prevent transmission of infectious pathogens that spread by direct or indirect contact with an infected person or a contaminated environment. This article reports a study investigating hand and environmental contamination levels when health care workers (HCWs) followed two different methods of removing gloves at two distances from the rubbish bin.

METHODS

Fifty HCWs performed a personal or causal glove removal method (pretest) and a Centers for Disease Control (CDC)-recommended glove removal method (posttest) at distances of 2 feet and 3 feet from the rubbish bin after the application of fluorescent solution (the simulated contaminant) onto their gloved hands.

RESULTS

The incidence of the small patch of fluorescent stain (<1 cm(2)) on the front of the doffed gloves was significantly lower in the posttest than in the pretest. The incidence of small and large patches (>1 cm(2)) on the front of the doffed gloves and on the cover of the rubbish bin was significantly lower at 3 feet than at 2 feet. Health care assistants had significantly higher levels of contamination than other HCWs in the pretest but not in the posttest. There was no significant difference in hand contamination rate between pretest and posttest based on distance from the rubbish bin and type of HCW.

CONCLUSION

The impact of the glove removal procedure and the distance to the bin in which used gloves are discarded should be taken into consideration on a daily basis, along with the supervision of infection control measures by minor staff.

SARS molecular epidemiology: a Chinese fairy tale of controlling an emerging zoonotic disease in the genomics era

Severe acute respiratory syndrome (SARS) was the first natural disaster that challenged the Chinese people at the beginning of the twenty-first century. It was caused by a novel animal coronavirus, never recognized or characterized before. This SARS coronavirus (SARS-CoV) exploited opportunities provided by 'wet markets' in southern China to adapt to the palm civet and human. Under the positive selection pressure of human host, certain mutated lineages of the virus became readily transmissible between humans and thus caused the epidemic of 2002-2003. This review will provide first-hand information, particularly from Guangdong, China, about the initial epidemiology, the identification of the aetiological agent of the disease, the molecular evolution study of the virus, the finding of SARS-like CoV in horseshoe bats and the mechanistic analysis for the cross-host tropism transition. The substantial scientific contributions made by the Chinese scientists towards understanding the virus and the disease will be emphasized. Along with the description of the scientific discoveries and analyses, the significant impact of these researches upon the public health measurement or regulations will be highlighted. It is aimed to appreciate the concerted and coordinated global response that controlled SARS within a short period of time as well as the research strategy and methodology developed along with this process, which can be applied in response to other public health challenges, particularly the future emerging/re-merging infectious diseases.

How often do you wash your hands? A review of studies of hand-washing practices in the community during and after the SARS outbreak in 2003

We reviewed evidence of hand-washing compliance in community settings during the 2003 SARS outbreak. Literature was searched through PubMed, Cochrane Library, Wan Fang database and Google. English and Chinese papers were reviewed. Studies containing data on hand-washing, self-reported or directly observed, in community settings were selected. Case-control studies and studies in healthcare settings were excluded. Fourteen studies were reviewed. Self-reported hand-washing compliance increased in the first phase of the SARS outbreak and maintained a high level 22 months after the outbreak. The decline of hand-washing in Hong Kong after SARS was relatively slow. A significant gender difference in hand-washing compliance (female > male) was found in eight studies. The importance of family support and 'significant female others' in hand hygiene promotion are noted. The impact of education is uncertain. Perceived susceptibility to and severity of SARS, and perceived efficacy of hand-washing in preventing SARS, also predicted self-reported hand-washing compliance.

Effectiveness of handwashing in preventing SARS: a review

This review examines the literature, including literature in Chinese, on the effectiveness of handwashing as an intervention against severe acute respiratory syndrome (SARS) transmission. Nine of 10 epidemiological studies reviewed showed that handwashing was protective against SARS when comparing infected cases and non‐infected controls in univariate analysis, but only in three studies was this result statistically significant in multivariate analysis. There is reason to believe that this is because most of the studies were too small. The evidence for the effectiveness of handwashing as a measure against SARS transmission in health care and community settings is suggestive, but not conclusive.

Contamination: a comparison of 2 personal protective systems

BACKGROUND

The purpose of this study was to examine the difference in self-contamination rates and levels of contact and droplet protection associated with enhanced respiratory and contact precautions (E-RCP) and a personal protective system that included a full body suit, personal protective equipment and a powered air-purifying respirator (PAPR).

METHODS

In this prospective, randomized, controlled crossover study, 50 participants donned and removed E-RCP and PAPR in random order. Surrogate contamination consisted of fluorescein solution and ultraviolet (UV) light- detectable paste, which was applied after each ensemble was donned. A blinded evaluator inspected participants for contamination using a UV lamp after removal of each ensemble. Areas of contamination were counted and measured in square centimetres. Donning and removal violations were recorded. The primary end point was the presence of any contamination on the skin or base clothing layer.

RESULTS

Participants wearing E-RCP were more likely to experience skin and base-clothing contamination; their contamination episodes measuring > or = 1 cm2 were more frequent, and they had larger total areas of contamination (all p < 0.0001). The anterior neck, forearms, wrists and hands were the likeliest zones for contamination. Participants donning PAPR committed more donning procedure violations (p = 0.0034). Donning and removing the PAPR system took longer than donning and removing E-RCP garments (p < 0.0001).

INTERPRETATION

Participants wearing E-RCP were more likely to experience contamination of their skin and base clothing layer. Those wearing PAPR required significantly more time to don and remove the ensemble and violated donning procedures more frequently.

When is quarantine a useful control strategy for emerging infectious diseases?

The isolation and treatment of symptomatic individuals, coupled with the quarantining of individuals that have a high risk of having been infected, constitute two commonly used epidemic control measures. Although isolation is probably always a desirable public health measure, quarantine is more controversial. Mass quarantine can inflict significant social, psychological, and economic costs without resulting in the detection of many infected individuals. The authors use probabilistic models to determine the conditions under which quarantine is expected to be useful. Results demonstrate that the number of infections averted (per initially infected individual) through the use of quarantine is expected to be very low provided that isolation is effective, but it increases abruptly and at an accelerating rate as the effectiveness of isolation diminishes. When isolation is ineffective, the use of quarantine will be most beneficial when there is significant asymptomatic transmission and if the asymptomatic period is neither very long nor very short.

Severe acute respiratory syndrome

Severe acute respiratory syndrome (SARS) was caused by a previously unrecognized animal coronavirus that exploited opportunities provided by 'wet markets' in southern China to adapt to become a virus readily transmissible between humans. Hospitals and international travel proved to be 'amplifiers' that permitted a local outbreak to achieve global dimensions. In this review we will discuss the substantial scientific progress that has been made towards understanding the virus-SARS coronavirus (SARS-CoV)-and the disease. We will also highlight the progress that has been made towards developing vaccines and therapies The concerted and coordinated response that contained SARS is a triumph for global public health and provides a new paradigm for the detection and control of future emerging infectious disease threats.

Severe acute respiratory syndrome: an update

PURPOSE OF REVIEW

An international outbreak of severe acute respiratory syndrome, a recently recognized syndrome caused by the newly identified severe acute respiratory syndrome-associated coronavirus, began in November 2002 and ended in July 2003. Since then, a large body of research on the syndrome has been published; the most updated developments are summarized here.

RECENT FINDINGS

Recent findings suggest that animal severe acute respiratory syndrome-like coronaviruses may have been transmitted to humans without detection for years before the recent outbreak, and that such transmission may be continuing today. The 2002-2003 outbreak probably originated from similar animal-to-human transmission, but selection and purification of the animal severe acute respiratory syndrome-like virus appears to have occurred, creating the more virulent severe acute respiratory syndrome-associated coronavirus. Recent studies have documented that severe acute respiratory syndrome-associated coronavirus is primarily transmitted via contact and/or respiratory droplets and that the combination of standard, contact, and droplet precautions is generally effective for its control. It has been shown that severe acute respiratory syndrome-associated coronavirus is typically relatively inefficiently transmitted, with the notable exception of transmission during superspreading events. Insights into the pathogenesis of severe acute respiratory syndrome have been made: one study suggests that human leukocyte antigen HLA-B*4601 is a possible risk factor for more severe disease, while another identifies angiotensin-converting enzyme 2 as a cellular receptor for severe acute respiratory syndrome-associated coronavirus. Promising treatments have been identified, including interferons, an anti-spike monoclonal antibody, and fusion inhibitors. In addition, many promising vaccines are currently in development.

SUMMARY

New findings regarding severe acute respiratory syndrome are continuing to be discovered at an unprecedented pace, permitting a better understanding of the disease and enabling better preparation for its possible return.