Fitted Filtration Efficiency of Double Masking During the COVID-19 Pandemic

Emerging infectious diseases, focus on infection prevention, environmental survival and germicide susceptibility: SARS-CoV-2, Mpox, and Candida auris

BACKGROUND

New and emerging infectious diseases continue to represent a public health threat. Emerging infectious disease threats include pathogens increasing in range (eg, Mpox), zoonotic microbes jumping species lines to cause sustained infections in humans via person-to-person transmission (SARS-CoV-2) and multidrug-resistant pathogens (eg, Candida auris).

MATERIALS AND METHODS

We searched the published English literature and reviewed the selected articles on SARS-CoV-2, Mpox, and Candida auris with a focus on environmental survival, contamination of the patient's hospital environment, susceptibility of the pathogen to antiseptics and disinfectants and infection prevention recommendations.

RESULTS

All three pathogens (ie, SARS-CoV-2, Mpox, and Candida auris) can survive on surfaces for minutes to hours and for Mpox and C auris for days. Currently available antiseptics (eg, 70%-90% alcohol hand hygiene products) are active against SARS-CoV-2, Mpox and C auris. The U.S Environmental Protection Agency provides separate lists of surface disinfectants active against SARS-CoV-2, Mpox, and C auris.

DISCUSSION

The risk of environment-to-patient transmission of SARS-CoV-2, Mpox and Candida auris, is very low, low-moderate and high, respectively. In the absence of appropriate patient isolation and use of personal protection equipment, the risk of patient-to-health care provider transmission of SARS-CoV-2, Mpox, and C auris is high, moderate and low, respectively.

CONCLUSIONS

Appropriate patient isolation, use of personal protective equipment by health care personnel, hand hygiene, and surface disinfection can protect patients and health care personnel from acquiring SARS-CoV-2, Mpox, and C auris from infected patients.

A novel method for the quantitative assessment of the fitted containment efficiency of face coverings

BACKGROUND

Face masks reduce disease transmission by protecting the wearer from inhaled pathogens and reducing the emission of infectious aerosols. Although methods quantifying efficiency for wearer protection are established, current methods for assessing face mask containment efficiency rely on measurement of a low concentration of aerosols emitted from an infected or noninfected individual.

METHODS

A small port enabled the introduction of 0.05 µm sodium chloride particles at a constant rate behind the mask worn by a study participant. A condensation particle counter monitored ambient particle numbers 60 cm in front of the participant over 3-minute periods of rest, speaking, and coughing. The containment efficiency (%) for each mask and procedure was calculated as follows: 100 × (1 - average ambient concentration with face covering worn/average ambient concentration with a sham face covering in place). The protection efficiency (%) was also measured using previously published methods. The probability of transmission (%) from infected to uninfected (a function of both the containment efficiency and the protection efficiency) was calculated as follows: {1 - (containment efficiency/100)}×{1 - (protection efficiency/100)}×100.

RESULTS

The average containment efficiencies for each mask over all procedures and repeated measures were 94.6%, 60.9%, 38.8%, and 43.2%, respectively, for the N95 mask, the KN95 mask, the procedure face mask, and the gaiter. The corresponding protection efficiencies for each mask were 99.0%, 63.7%, 45.3%, and 24.2%, respectively. For example, the transmission probability for 1 infected and 1 uninfected individual in close proximity was ∼14.2% for KN95 masks, compared to 36%-39% when only 1 individual wore a KN95 mask.

CONCLUSION

Overall, we detected a good correlation between the protection and containment that a face covering afforded to a wearer.

The Adverse and Advantage Effects of Wearing a Facemask in Thai Children: A Survey During the COVID-19 Pandemic

BACKGROUND

There is little information on facemask use during the COVID-19 pandemic in the pediatric population. This became the main purpose of the present study to investigate demographic data of facemask wearing in children, types, and length of facemask, as well as the benefits, drawbacks, and negative consequences of facemask wearing in this population.

METHODS

A cross-sectional study was conducted using a structured questionnaire sent via Google Forms. Caregivers for consecutive convenience were asked in the survey (parents of children under the age of 18).

RESULTS

A total number of 706 children were enrolled. There were 320 boys (45.33%), and 386 girls (54.67%). The children's ages range between 4 months and 18 years, with a median age of 9 years. A surgical mask (549, 77.76%) was the most frequent type of facemask in the study population, followed by a cloth mask (86, 12.18%). Facemasks have been shown to be beneficial in the pediatric population. When compared to a former time when facemasks were not used routinely, there were considerably fewer respiratory infections, reduced diarrhea symptoms, and a drop in hospital admissions. In 317 cases (44.9%), children were shown to have negative consequences from wearing facemasks. The most prevalent adverse effect observed in the study population was non-cutaneous (respiratory discomfort/breathing difficulty) which were found in 240 cases (33.99%). Double masking method (surgical + surgical) and wearing a facemask oversize revealed a higher risk in the presence of facemask adverse effects, whereas wearing a proper size facemask reduces the risk of adverse effects from facemask use in children (Adjusted OR [95% CI] = 0.55 [0.38-0.78], P .0003).

CONCLUSIONS

Wearing a proper-size facemask reduces the risk of adverse effects from facemask use in children. The future suggestion of an appropriate facemask size for a certain age will aid in the avoidance of facemask adverse effects in the pediatric population.

Improvement in Fitted Filtration Efficiency of N95 Respirators With Escalating Instruction of the Wearer

Introduction

Fitted filtration performance of an N95 respirator may benefit from differing levels of instructions.

Methods

Using a modified Occupational Safety and Health Administration fit test protocol, we measured fitted filtration efficiency for an N95 respirator in 21 screened, healthy participants given 4 levels of escalating instruction: (1) uninstructed (baseline), (2) written/pictorial manufacturer instructions, (3) step-by-step video demonstration, and (4) staff instruction (visual inspection of respirator fit and verbal suggestions to adjust when applicable).

Results

Baseline fitted filtration efficiency was not significantly different between participants with or without previous experience of N95 use. Clear improvements in fitted filtration efficiency were observed progressing from baseline (average=86.1%) to manufacturer paper instructions (93.3%), video instructions (97.5%), and post staff intervention (98.3%). Baseline fitted filtration efficiency values were significantly lower than those after video instruction (p<0.037) and staff intervention (p<0.033) sessions.

Conclusions

Beyond uninstructed wear or provision of manufacturer instructions, efforts to train and instruct users in proper respirator fit principles with visual feedback are likely to yield benefits to public health outcomes in reducing respiratory exposure during air quality emergencies such as airborne viral outbreaks and wildland fires.

Can disposable masks be worn more than once?

Disposable facemasks are a primary tool to prevent the transmission of SARS-COV-2 during the COVID-19 pandemic. However, plastic waste generated from their disposal represents a significant environmental problem that can be reduced by maximizing the service life of disposable masks. We evaluated the effect of repeated wearing on the fitted filtration efficiency (FFE) of N95, KF94, KN95, and procedure/surgical masks. The FFEs of masks were compared following extended wearing with and without washing. Results reveal that most disposable facemasks can retain a high level of their baseline FFE after extended wearing, even after 40 h of wearing. Laundering disposable masks degraded FFE in some instances. We conclude that the durability of disposable facemask performance is considerably longer than their intended single use indication, suggesting that reusing disposable masks is a safe means of reducing plastic waste in the environment.

Universal Use of N95 Respirators in Healthcare Settings When Community Coronavirus Disease 2019 Rates Are High

The Centers for Disease Control and Prevention recommends N95 respirators for all providers who see patients with possible or confirmed coronavirus disease 2019 (COVID-19). We suggest that N95 respirators may be just as important for the care of patients without suspected COVID-19 when community incidence rates are high. This is because severe acute respiratory syndrome coronavirus 2 is most contagious before symptom onset. Ironically, by the time patients are sick enough to be admitted to the hospital with COVID-19, they tend to be less contagious. The greatest threat of transmission in healthcare facilities may therefore be patients and healthcare workers with early occult infection. N95 respirators' superior fit and filtration provide superior exposure protection for healthcare providers seeing patients with early undiagnosed infection and superior source control to protect patients from healthcare workers with early undiagnosed infection. The probability of occult infection in patients and healthcare workers is greatest when community incidence rates are high. Universal use of N95 respirators may help decrease nosocomial transmission at such times.

Double Face Mask Use for COVID-19 Infection Prevention and Control Among Medical Students at Makerere University: A Cross-Section Survey

INTRODUCTION

The second wave of COVID-19 greatly affected the health care and education systems in Uganda, due to the infection itself and the lockdowns instituted. Double masking has been suggested as a safe alternative to double-layered masks, where the quality of the latter may not be guaranteed. This study aimed to determine patterns of double mask use among undergraduate medical students at Makerere University, Uganda.

METHODS

We conducted a descriptive cross-sectional study using an online questionnaire. All students enrolled at the College of Health Sciences; Makerere University received the link to this questionnaire to participate. Logistic regression analysis was used to assess factors associated with double mask use.

RESULTS

A total of 348 participants were enrolled. The majority (61.8%) were male; the median age was 23 (range: 32) years. Up to 10.3%, 42%, and 4.3% reported past COVID-19 positive test, history of COVID-19 symptoms, and having comorbidities, respectively. Up to 40.8% had been vaccinated against COVID-19. More than half (68.7%) believed double masking was superior to single masking for COVID-19 IPC, but only 20.5% reported double masking. Participants with a past COVID-19 positive test [aOR: 2.5; 95% CI: 1.1-5.8, p = 0.026] and participants who believed double masks had a superior protective advantage [aOR: 20; 95% CI: 4.9-86.2, p < 0.001] were more likely to double mask. Lack of trust in the quality of masks (46.5%) was the most frequent motivation for double masking, while excessive sweating (68.4%), high cost of masks (66.4%), and difficulty in breathing (66.1%) were the major barriers.

CONCLUSION

Very few medical students practice double masking to prevent COVID-19. Coupled with inconsistencies in the availability of the recommended four-layered masks in Uganda and increased exposure in lecture rooms and clinical rotations, medical students may be at risk of contracting COVID-19.

Efficacy of homemade face masks against human coughs: Insights on penetration, atomization, and aerosolization of cough droplets

Ever since the emergence of the ongoing COVID-19 pandemic, the usage of makeshift facemasks is generally advised by policymakers as a possible substitute for commercially available surgical or N95 face masks. Although such endorsements could be economical and easily accessible in various low per-capita countries, the experimental evidence on the effectiveness of such recommendations is still lacking. In this regard, we carried out a detailed experimental investigation to study the fate of a large-sized surrogate cough droplet impingement at different velocities (corresponding to mild to severe coughs) on various locally procured cloth fabrics. Observation shows that larger ejected droplets (droplets that would normally settle as fomites in general) during a coughing event have enough momentum to penetrate single-layer cloth masks; the penetrated volume atomize into smaller daughter droplets that fall within aerosol range, thereby increasing infection potential. Theoretically, two essential criteria based on the balances of viscous dissipation-kinetic energy and surface tension-kinetic energy effects have been suggested for the droplet penetration through mask layers. Furthermore, a new parameter called η (the number density of pores for a fabric) is developed to characterize the volume penetration potential and subsequent daughter droplet size. Finally, the effect of mask washing frequency is analyzed. The outcomes from the current study can be used as a guide in selecting cloth fabrics for stitching multi-layered.

Maintaining mask momentum in transplant recipients

The widespread use of facemasks has been a crucial element in the control of the SARS‐CoV‐2 pandemic.  With mounting evidence for mask efficacy against respiratory infectious diseases and greater acceptability of this intervention, it is proposed that masking should continue after the pandemic has abated to protect some of our most vulnerable patients, recipients of stem cell and solid organ transplants. This may involve not only masking these high‐risk patients, but possibly their close contacts and the healthcare workers involved in their care. We review the evidence for mask efficacy in prevention of respiratory viruses other than SARS‐CoV‐2 and address the burden of disease in transplant recipients.  Although we acknowledge that there are limited data on masking to prevent infection in transplant recipients, we propose a framework for the study and implementation of routine masking as a part of infection prevention interventions after transplantation.

Experimental investigation of indoor aerosol dispersion and accumulation in the context of COVID-19: Effects of masks and ventilation

The ongoing COVID-19 pandemic has highlighted the importance of aerosol dispersion in disease transmission in indoor environments. The present study experimentally investigates the dispersion and build-up of an exhaled aerosol modeled with polydisperse microscopic particles (approximately 1 μm mean diameter) by a seated manikin in a relatively large indoor environment. The aims are to offer quantitative insight into the effect of common face masks and ventilation/air purification, and to provide relevant experimental metrics for modeling and risk assessment. Measurements demonstrate that all tested masks provide protection in the immediate vicinity of the host primarily through the redirection and reduction of expiratory momentum. However, leakages are observed to result in notable decreases in mask efficiency relative to the ideal filtration efficiency of the mask material, even in the case of high-efficiency masks, such as the R95 or KN95. Tests conducted in the far field ( 2   m distance from the subject) capture significant aerosol build-up in the indoor space over a long duration ( 10   h ). A quantitative measure of apparent exhalation filtration efficiency is provided based on experimental data assimilation to a simplified model. The results demonstrate that the apparent exhalation filtration efficiency is significantly lower than the ideal filtration efficiency of the mask material. Nevertheless, high-efficiency masks, such as the KN95, still offer substantially higher apparent filtration efficiencies (60% and 46% for R95 and KN95 masks, respectively) than the more commonly used cloth (10%) and surgical masks (12%), and therefore are still the recommended choice in mitigating airborne disease transmission indoors. The results also suggest that, while higher ventilation capacities are required to fully mitigate aerosol build-up, even relatively low air-change rates ( 2   h - 1 ) lead to lower aerosol build-up compared to the best performing mask in an unventilated space.