Respiratory Protection Against Emerging Infectious Diseases: Face Masks, Respirators, and Tools for Choosing Between Them

Electrospun nonwoven fabric of poly(ε-caprolactone)/n-phosphonium chitosan for antiviral applications: Fabrication, characterization, and potential efficacy

This work reports the virucidal properties of nonwoven fibers developed via electrospinning with polycaprolactone (PCL) and chitosan quaternized with phosphonium salt (NPCS), emphasizing the influence of NPCS concentration on the structure of fibers and their performance against the MHV-3 coronavirus. The addition of NPCS enhances solutions conductivity and viscosity, leading to fibers containing a finer porous structure with a more hydrophilic and smoother surface, thereby making them a potent barrier against respiratory particles, which is a key factor for protective face masks. In terms of degradation, NPCS paced-up the process, suggesting potential environmental benefits. PCL/NPCS (90/10) fibers exhibit a 99 % coronavirus inhibition within a five-minute exposure without cellular toxicity, while also meeting breathability standards for medical masks. These findings suggest the use of NPCS as a promising strategy to design materials with remarkable virucidal performance and physical characteristics that reinforce their use in the field of biomaterials engineering.

Literature review of physiological strain of personal protective equipment on personnel in the high-consequence infectious disease isolation environment

BACKGROUND

Heat strain and dehydration can affect an individual's physical and mental performance. The purpose of this review was to examine the literature for the impact of heat strain on health care workers (HCWs) who care for patients with high-consequence infectious diseases (HCIDs) while wearing personal protective equipment (PPE), discuss the risks of impaired safety caused by heat strain and dehydration in HCID environments, identify attempts to combat PPE-related heat strain, recognize limitations, and provide suggestions for further research.

METHODS

A literature search was performed in PubMed or MEDLINE and Google Scholar. Authors screened abstracts for inclusion criteria and reviewed articles if the abstracts were considered to include information relevant to the aim.

RESULTS

The search terms yielded 30 articles that were sorted based on environment setting, physiological impact, and interventions.

DISCUSSION

The safety of the HCWs and patients can be enhanced through the development and usage of cooler, more comfortable PPE materials and ensembles to help slow the rate of dehydration and support the regulation of core body temperature.

CONCLUSIONS

Heat strain caused by wearing PPE is an occupational health concern for HCWs in the high-risk environment, that is, HCID care. Future studies are needed to develop innovative PPE ensembles that can reduce heat strain and improve well-being.

Fabrication of a highly protective 3D-printed mask and evaluation of its viral filtration efficiency using a human head mannequin

Facemasks are one of the most effective and low-cost prophylactics for COVID-19. In the spring 2020, when a severe shortage of facemasks occurred worldwide, various types of 3D-printed masks were designed and proposed. However, the protective effects conferred by most of these masks were not experimentally evaluated. Here, we provide a new simple design of 3D-printed mask and evaluate its protective effect in a viral filtration test using a human head mannequin. The developed mask can be constructed with a low-cost 3D printer, with an approximate production cost of US $4. This mask has three parts: the main part, wearing parts, and a piece of non-woven fabric filter. The volume of the filter, which needs to be changed daily, was reduced to approximately 1/10 of that of commercially available surgical masks used in this study. The developed mask is fabricated from polylactic acid, a biodegradable plastic, and its surface contour contacting the face may be adjusted after softening the material with hot water at 60-80°C. The viral filtration efficiency of the developed mask was found to be over 80%. This performance is better than that of commercially available facemasks, such as surgical masks and cloth masks, and equal to those of KN95 and KF94.

Use of powered air-purifying respirator(PAPR) as part of protective equipment against SARS-CoV-2-a narrative review and critical appraisal of evidence

BACKGROUND

The last 2 decades have seen an increasing frequency of zoonotic origin viral diseases leaping from animal to human hosts including Severe Acute Respiratory Syndrome Coronaviruses (SARS-CoV-2). Respiratory component of the infectious disease program against SARS-CoV-2 incorporates use of protective airborne respiratory equipment.

METHODS

In this narrative review, we explore the features of Powered Air Purifying Respirators (PAPR) as well as logistical and evidence-based advantages and disadvantages.

RESULTS

Simulation study findings support increased heat tolerance and wearer comfort with a PAPR, versus decreased communication ability, mobility, and dexterity. Although PAPRs have been recommended for high-risk procedures on suspected or confirmed COVID-19 patients, this recommendation remains controversial due to lack of evidence. Guidelines for appropriate use of PAPR during the current pandemic are sparse. International regulatory bodies do not mandate the use of PAPR for high-risk aerosol generating procedures in patients with SARS-CoV-2. Current reports of the choice of protective respiratory technology during the SARS-CoV-2 pandemic are disparate. Patterns of use appear to be related to geographical locations.

DISCUSSION

Field observational studies do not indicate a difference in healthcare worker infection utilizing PAPR devices versus other compliant respiratory equipment in healthcare workers performing AGPs in patients with SARS-CoV-2. Whether a higher PAPR filtration factor translates to decreased infection rates of HCWs remains to be elucidated. Utilization of PAPR with high filtration efficiency may represent an example of "precautionary principle" wherein action taken to reduce risk is guided by logistical advantages of PAPR system.

Electrospun ultrafine fibers for advanced face masks

The outbreak of Coronavirus Disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has triggered great global public health concern. Face masks are essential tools to reduce the spread of SARS-CoV-2 from human to human. However, there are still challenges to prolong the serving life and maintain the filtering performance of the current commercial mask. Filters composed of ultrafine fibers with diameter down to tens of nanometers have the potential to physically block viruses. With adjustable composition and nanostructures, the electrospun ultrafine fiber filter is possible to achieve other necessary functions beyond virus blocking, such as antiviral, transparent, and degradable, making it an important part of fighting the epidemic. In this review, beginning with the basic information of the viruses, we summarize the knowledge of masks and respirators, including the filtering mechanism, structure, classification, and standards. We further present the fabrication method, filtering performance, and reusable potential of electrospun ultrafine fiber-based masks. In the end, we discuss the development directions of ultrafine fibers in protective devices, especially their new functional applications and possible contributions in the prevention and control of the epidemic.