Comparison of Fit for Sealed and Loose-Fitting Surgical Masks and N95 Filtering Facepiece Respirators

Comparison of the inward leakage rate between N95 filtering facepiece respirators and modified surgical masks during the COVID-19 pandemic

BACKGROUND

Owing to shortage of surgical and N95 filtering facepiece respirators (FFRs) during the COVID-2019 pandemic, various masks were developed to prevent infection. This study aimed to examine the inward leakage rate (ILR) of sealed face masks and modified surgical masks using a quantitative fit test and compared it with the ILR of unmodified N95 FFRs.

METHODS

We conducted paired comparisons of ILRs of bent nose-fit wire masks, double masks, and N95 FFRs from October to December 2021. To measure the protective effectiveness of masks, participants wore masks, and the number of particles outside and inside the mask were measured. The ILR was based on the percentage of particles entering the mask using a fit tester.

RESULTS

We enrolled 54 participants (20 men and 34 women) in this study. The median ILR for surgical masks without and with a W-shaped bend in the nose-fit wire were 96.44% and 50.82%, respectively. The nose-fit wire adjustment reduced the ILR of surgical masks by a mean of 28.57%, which was significantly lower than the ILR without adjustment (P < 0.001). For double masks, with surgical or polyurethane masks on top of the W-shaped mask, the ILR did not differ significantly from that of N95. Although the filtration performance of double surgical masks matched that of N95 masks, their ILR was notably higher, indicating that double masks do not provide equivalent protection.

CONCLUSIONS

Wearing N95 masks alone is effective in many cases. However, surgical mask modifications do not guarantee consistent effectiveness. Properly selected, sealed masks with a good fit overcome leakage, emphasizing their crucial role. Without evidence, mask-wearing may lead to unexpected infections. Education based on quantitative data is crucial for preventing adverse outcomes.

Effect of Face Masking on Transmission of SARS-CoV-2

The efficacy of face masking for the public is not convincing to prevent the transmission of respiratory tract viruses such as SARS-CoV-2 when the criteria of evidence-based medicine are applied. This finding is mainly explained by the results from randomized-controlled trials (RCTs) when a high prevalence of the infection and a high compliance in mask wearing was assured. Throughout these studies no significant protective effect was observed. Observational studies with surgical masks describe a significant protective effect, but are prone to confounders such as physical distance. Respirators do not provide an additional health benefit compared to surgical or medical masks (RCTs). Community masks can even increase the risk of infection (RCTs). Based on the categories of evidence-based medicine, the efficacy results can best be categorized as conflicting evidence. Many relevant adverse events are described when masks are worn for hours such as dyspnea (12.2-52.8%), headache (3.9-73.4%), pruritus (0.0-60.0%), and skin reactions (0.0-85.0%). Their frequency is often higher with respirators. In future pandemics, masks should only be recommended or mandated for settings in which a clinically relevant health benefit can be expected, defined as the prevention of severe, critical or fatal disease, that clearly outweighs the expectable associated adverse reactions.

The Impact of Personal Protective Equipment on Healthcare Workers on COVID-19 Duty in a Tertiary Care Hospital in South India

Context The proper usage of personal protective equipment (PPE) must be prioritised for health care workers (HCWs), where shortages and prolonged use of personal protective equipment can threaten safety in essential health services. Aims To evaluate the effect of personal protective equipment on the health and well-being of HCWs, physicians, nurses, and technicians on duty for COVID-19 rotational postings. Settings and design This cross-sectional study was done by simple random sampling. Methods and materials This study was conducted at a tertiary care centre in South India to assess the utilisation of personal protective equipment (PPE) during the second wave of COVID-19. A physical questionnaire was distributed to a total of 266 healthcare workers, aged 20 to 50, who had worked for a minimum of three consecutive days between May and August 2021. The objective of the study was to evaluate the effectiveness of PPE use among healthcare workers during the second wave of the COVID-19 pandemic. Statistical analysis The data analysis in this study was conducted using IBM Statistical Package for Social Sciences (SPSS) version 19 (IBM Corp., Armonk, New York). The mean and standard deviation, or median, were used to present continuous variables, while frequency and percentage were used to present categorical variables. Furthermore, the minimum sample size required for this study was calculated to be 246 participants. Results The survey included 266 healthcare workers. The mean+/-SD of age was 28.18+/-5.64 and consisted of females (54.51%) and males (45.48%). The postings were in emergency (13.15%), intensive care unit (30.82%), and ward (56.01%), respectively. The HCWs who used PPE for four to seven days reported more symptoms than those who used it for one to three days. Discomforts experienced while wearing PPE were chest suffocation (49.62%), difficulty in performing intubation (36.09%), difficulty in seeing clearly (68.79%), dizziness (49.62%), excessive sweating (75.56%), micturition desire (52.63%), nausea (42.48%), retro-auricular pain (56.76%), stomach burns (27.44%), and thirst or dry throat (78.57%). The symptoms suffered after doffing were tiredness (69.17%), dry mouth (67.29%), dizziness (43.60%), headache (55.63%), chest suffocation (36.46%), dry skin (57.14%), reduced ability to concentrate (48.12%), dark-coloured urine (55.63%), reduced alertness (42.48%), and stomach burns (28.94%). The first thoughts after doffing were to drink water (68.42%), eat something (36.09%), clean yourself (61.27%), urinate (33.08%), and have some rest (29.32%), respectively. 81 (30.45%). The HCWs suffered skin injuries while wearing gloves. The time for restoring after a shift was 12 hours (37.59%), 24 hours (34.21%), 36 hours (11.65%), and 48 hours (16.59%). Pressure sores were reported on the forehead by 53 (19.92%) participants, the nose by 54 (20.30%), the cheek by 31 (11.65%), and behind the ear by 77 (65.71%) participants. The optimal size of PPE was experienced only by 76 (28.57%) participants, while 73 (27.44%) of them felt tight and 117 (43.98%) felt loose. Conclusions To minimise discomfort while managing infectious diseases, HCWs can adopt several practices like taking regular breaks, ensuring humane working hours, utilising high-quality PPE, and wearing properly fitting gear. By implementing these measures, HCWs can enhance their ability to handle infectious diseases effectively while prioritising their comfort and well-being.

Measuring the quantity of harmful volatile organic compounds inhaled through masks

An increase in the concentration of environmental particulate matter and the spread of the COVID-19 virus have dramatically increased our time spent wearing masks. If harmful chemicals are released from these masks, there may be harmful effects on human health. In this study, the concentration of volatile organic compounds (VOCs) emitted from some commonly used masks was assessed qualitatively and quantitatively under diverse conditions (including different mask material types, time between opening the product and wearing, and mask temperature). In KF94 masks, 1-methoxy-2-propanol (221 ± 356 µg m-3), N,N-dimethylacetamide (601 ± 450 µg m-3), n-hexane (268 ± 349 µg m-3), and 2-butanone (160 ± 244 µg m-3) were detected at concentrations 22.9-147 times higher than those found in masks made from other materials, such as cotton and other functional fabrics. In addition, in KF94 masks, the total VOC (TVOC) released amounted to 3730 ± 1331 µg m-3, about 14 times more than that released by the cotton masks (267.5 ± 51.6 µg m-3). In some KF94 masks, TVOC concentration reached over 4000 µg m-3, posing a risk to human health (based on indoor air quality guidelines established by the German Environment Agency). Notably, 30 min after KF94 masks were removed from their packaging, TVOC concentrations decreased by about 80% from their initial levels to 724 ± 5.86 µg m-3; furthermore, 6 h after removal, TVOC concentrations were found to be less than 200 µg m-3. When the temperature of the KF94 masks was raised to 40 oC, TVOC concentrations increased by 119-299%. Since the types and concentrations of VOCs that will be inhaled by mask wearers vary depending on the mask use conditions, it is necessary to comply with safe mask wearing conditions.

Does the fit of personal protective equipment affect functional performance? A systematic review across occupational domains

OBJECTIVE

To explore the effect of personal protective equipment (PPE) fit on functional performance across a range of occupational domains.

BACKGROUND

PPE introduces an ergonomic, human systems integration, and mass burden to the wearer, and these factors are thought to be amplified if PPE is ill-fitting. However, few studies have considered the role of fit (static, dynamic, and cognitive) when evaluating PPE-related performance detriments in occupational settings.

METHOD

A systematic literature review was conducted to identify relevant studies, which were then critically appraised based on methodological quality and collated to compare key findings and present evidence-based recommendations for future research directions across a range of occupational domains.

RESULTS

16 published studies met the inclusion criteria, 88% of which found that the fit of PPE had a statistically significant effect on occupational performance. Poorly sized PPE resulted in slower or increased reaction time; decreased range of motion or mobility; decreased endurance or tolerance; decreased pulmonary function; and altered muscle activation. Limited research met the inclusion criteria and those that did had risks of bias in methodology quality.

CONCLUSION

Future research evaluating the effect of PPE on performance in occupational settings should aim to recruit a more representative population; consider sex as a covariate; quantify and evaluate PPE fit and performance when integrated with all relevant equipment items; include outcome measures related to all three categories of fit (static, dynamic, cognitive); and assess performance of operationally relevant tasks.

Utilization of a mask fitter or micropore tape to improve the fit of a surgical mask

PURPOSE

This study aimed to test the face seal of a surgical mask modified using a custom-made mask fitter or by sealing all borders with micropore tape, in comparison to the N95 mask as a gold standard.

METHODS

Fifteen participants were assigned to wear an N95 mask, a surgical mask sealed with a mask fitter, and a surgical mask sealed with micropore tape. A quantitative fit test was performed using a Portacount respirator fit tester in 4 different actions: bending over, talking, moving the head from side to side, and moving the head up and down.

RESULTS

The N95 showed the highest overall fit factor score (134.67 ± 66.62), passing Occupational Safety and Health Administration (OSHA) standards. The surgical mask alone had the lowest overall fit factor score of 4.73 ± 3.30. Modification of the surgical mask using a mask fitter or micropore tape significantly increased the overall fit factor to 35.33 ± 14.58 and 29.33 ± 9.73, respectively. This pattern was similar for all exercises.

CONCLUSION

The N95 was the only mask type that passed the OSHA standard for protection. Use of a mask fitter or micropore tape significantly increased the face seal of a surgical mask. This could offer useful levels of protection during a non-aerosol dental procedure.

A critical review on the role of leakages in the facemask protection against SARS-CoV-2 infection with consideration of vaccination and virus variants

The protection provided by facemasks has been extensively investigated since the beginning of the SARS-CoV-2 outbreak, focusing mostly on the filtration efficiency of filter media for filtering face pieces (FFP), surgical masks, and cloth masks. However, faceseal leakage is a major contributor to the number of potentially infectious airborne droplets entering the respiratory system of a susceptible individual. The identification of leaking spots and the quantification of leaking flows are crucial to estimate the protection provided by facemasks. This study presents a critical review on the measurement and calculation of facemask leakages and a quantitative analysis of their role in the risk of SARS-CoV-2 infection. It shows that the pairing between the mask dimensions and the wearer's face is essential to improve protection efficiency, especially for FFP2 masks, and summarizes the most common leaking spots at the interface between the mask and the wearer's face. Leakage is a crucial factor in the calculation of the protection provided by facemasks and outweighs the filtration performances. The fit factors measured among mask users were summarized for different types of face protection. The reviewed data were integrated into a computational model to compare the mitigation impact of facemasks with vaccination with consideration of new variants of SARS-CoV-2. Combining a high adoption rate of facemasks and a high vaccination rate is crucial to efficiently control the spread of highly infectious variants.

Infection Prevention Strategies Concordance in Canadian Dental Schools during COVID-19 Pandemic

Objective

The aim of this research was to identify variation in specific infection prevention and control (IPC) strategies across all dental schools in Canada and to evaluate the concordance concerning COVID-19 pandemic-related IPC strategies reported by clinic directors or IPC officers (CDs/IPCOs) and those reported by students, staff, and faculty in the schools.

Method

A cross-sectional analysis within a prospective cohort study. Participants in the cohort study reported IPC strategies used in their schools during April or May 2021. Independently, CDs/IPCOs reported IPC strategies in school protocols in July 2021.

Results

Of the 600 participants recruited, 332 participants who were involved in the provision of in-person dental care were further analysed. Of the 16 IPC strategies investigated, only 3 were reported by CDs/IPCOs to be used at all schools, and another 8 strategies were used by 8 or 9 of 10 or by 1 of 10 schools, indicating that concordance across schools was good for 11 of 16 strategies. Agreement between study participants and the CDs/IPCOs varied considerably by strategy (ranging between 50% and 100%) and by school (ranging between 42.9% and 97.2%). The strategies with the highest mean agreement percentage across schools were “screening or interviewing patients before appointment for COVID-19–related symptoms” (92.7%) and “checking the temperature of the staff members at least once a day using a thermometer” (91.5%).

Conclusions

The level of agreement in the use of strategies between participants working in clinics and CDs/IPCOs varied considerably by strategy and by school. Given the low COVID-19 infection rates in dental schools and the reported differences in IPC protocols, key strategies should be identified. During the pandemic, IPC protocols in Canadian dental schools evolved rapidly. Comparing different strategies might help develop a unified standard IPC protocol.

Knowledge Level on Infection Control among Romanian Undergraduate and Postgraduate Dental Students

Background and Objectives: Infection control practices in dentistry should be continuously evaluated. The aim of the present study was to assess the knowledge of dental students from Iași, Romania about infection control in the dental office. Materials and Methods: Dental students and resident dentists attending the “Grigore T. Popa” University of Medicine and Pharmacy in Iași were randomly selected in accordance with ethical guidelines, and a cross-sectional, questionnaire-based online study was conducted. The questionnaire included 21 items about infection control in dentistry. A descriptive statistical analysis was performed, and the chi-square test was used for data comparison, with a cutoff point of 0.05 for statistical significance. Results: The study sample included 150 subjects (75.3% female and 24.7% male) with a mean age of 25.71 ± 4.54 years. Mode of infection transmission was known by 74% of the subjects, and 76% were aware of standard precautions, with significant differences by the year of study (p = 0.012, r = 0.002). A percentage of 20% of subjects knew the means of transmission of the hepatitis B virus (HBV) (p = 0.032, r = 0.166). Most of the subjects were not vaccinated against HBV (p = 0.002, r = −0.274). Notions of high-level disinfection and sterilization were confused by 19.5% of the subjects. Only 22% of the subjects knew the correct processing of handpieces (p = 0.048, r = −0.071). The sources of information were diverse for 64.66% of the respondents, while 31.33% of them used courses and seminars only. Conclusions: There is a need for improvement in the level of knowledge on infection control for both dental students and residents.

Quantitative Fit Test of a 3D Printed Frame Fitted Over a Surgical Mask: An Alternative Option to N95 Respirator

Background

COVID-19 has spread worldwide and caused severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to numerous dead cases. However, with the new COVID-19 outbreaks, there is a shortage of personal protective equipment (PPE) especially N95 masks worldwide including Thailand. This issue had placed the health professional in great need of an alternative mask.

Aim

This study aimed to measure the fit factor of 3D printed frames by quantitative fit testing (QNFT) to find an alternative facemask by using a mask fitter together with 2 different kinds of the American Society for Testing and Materials (ASTM) level 1 surgical mask.

Materials and Methods

Two commonly used surgical masks (Sultan Com-Fit Super Sensitive Ear Loop Mask or “White Mask Group,” not water-resistant, and Sultan Blue Com-Fit Super High Filtration Ear Loop Mask or “Blue Mask Group,” water-resistant) with and without 3D printed frame covering. The fit performance was measured by a quantitative fit test (QNFT) device (PortaCount, model 8048, TSI Incorporated, Minnesota, USA) accepted by the Occupational Safety and Health Administration (OSHA). The PortaCount device, which is based on a miniature continuous flow condensation nucleus counter (CNC), assesses the respiratory fit by comparing the concentration of ambient dust particles outside the surgical mask to the concentration that has leaked into the surgical mask. The ratio of these two concentrations (C_out/C_in) is called the fit factor. A fit factor of a 3D printed frame of at least 100 is required and considered as a pass level.

Results

We found that the mask fitter improves the overall performance of surgical masks significantly. The improved performance is comparable to that of N95.

Conclusion

The mask fitter improves the performance of surgical masks. The authors suggested that further study on frame material, shape, and expanded sample size would be beneficial to society.

SARS-CoV-2 Aerosol Transmission Indoors: A Closer Look at Viral Load, Infectivity, the Effectiveness of Preventive Measures and a Simple Approach for Practical Recommendations

There is uncertainty about the viral loads of infectious individuals required to transmit COVID-19 via aerosol. In addition, there is a lack of both quantification of the influencing parameters on airborne transmission and simple-to-use models for assessing the risk of infection in practice, which furthermore quantify the influence of non-medical preventive measures. In this study, a dose-response model was adopted to analyze 25 documented outbreaks at infection rates of 4-100%. We show that infection was only possible if the viral load was higher than 108 viral copies/mL. Based on mathematical simplifications of our approach to predict the probable situational attack rate (PARs) of a group of persons in a room, and valid assumptions, we provide simplified equations to calculate, among others, the maximum possible number of persons and the person-related virus-free air supply flow necessary to keep the number of newly infected persons to less than one. A comparison of different preventive measures revealed that testing contributes the most to the joint protective effect, besides wearing masks and increasing ventilation. In addition, we conclude that absolute volume flow rate or person-related volume flow rate are more intuitive parameters for evaluating ventilation for infection prevention than air exchange rate.

Respiratory Protection Effect of Ear-loop-type KF94 Masks according to the Wearing Method in COVID-19 Pandemic: a Randomized, Open-label Study

BACKGROUND

Ear-loop-type Korean Filter 94 masks (KF94 masks, equivalent to the N95 and FFP2) are broadly used in health care settings in Korea for the coronavirus disease 2019 pandemic.

METHODS

A prospective randomized open-label study was designed to identify differences in the fitting performance between mask wearing methods in three different types of KF94 mask with ear loops between January to March 2021. General-fitting involved wearing an ear-loop-type KF94 mask, and tight-fitting involved wearing a mask aided by a clip connecting the ear loops. Each of the 30 participants wore three types of masks according to a randomly assigned order in both methods and performed a total of six quantitative fit tests (QNFTs) according to the occupational safety and health administration protocol.

RESULTS

All fit factors (FFs) measured by the QNFT were significantly higher for tight-fitting method with the clip in all KF94 masks (P < 0.001). However, the total FFs were very low, with a median (interquartile range) of 6 (3-23) and 29 (9-116) for general-fitting and tight-fitting, respectively. When wearing tightly, the horizontal 3-fold type mask with adjustable ear-loop length had the highest FF, with a median of 125, and the QNFT pass rate (FF ≥ 100) increased significantly from 4 (13%) to 18 (60%).

CONCLUSION

Even with sufficient filter efficiency, ear-loop-type-KF94 masks do not provide adequate protection. However, in relatively low-risk environments, wearing a face-seal adjustable KF94 mask and tight wearing with a clip can improve respiratory protection for healthcare workers.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04794556.

The defects of lace-up surgical masks and related solutions in operating rooms

BACKGROUND

It is difficult to make a lace-up surgical mask fit tightly to the face with conventional wearing methods because of the strings' poor tension, resulting in some air flowing through the gap. We introduced two feasible new wearing methods and obtained satisfactory experimental results.

METHODS

The wearing of surgical masks by staff was investigated through observation and interview in operation rooms. The required time to don, close-fitting rates, and satisfaction of the conventional method and the two new recommended methods were counted and compared, according to the subjects' experience. The differences between the three wearing methods on the microbial contamination of the sterile area were explored in a mock operation.

RESULTS

In the subjects' experience, the close-fitting rates were 47.0%, 92.0% and 100.0% in the conventional, Three Knots, and Elastic Band groups, respectively (P<0.001); the satisfaction scores evaluated by numerical rating scale from 0 to 10 were 5.06 ± 2.22, 6.89 ± 1.86 and 7.10 ± 1.72, respectively (P<0.001); the required times were 14.32 ± 2.20, 25.76 ± 5.13 and 27.37 ± 5.11 s, respectively (P<0.001). In the mock operation, there were significant differences between the conventional and Three Knots groups (37.5 (13) vs 18 (8) cfu, P<0.001), as well as between the conventional and Elastic Band groups (37.5 (13) vs 17(10) cfu, P<0.001).

CONCLUSIONS

The recommended new wearing methods had the advantages of closer fit, higher satisfaction rates, were more comfortable, and resulted in lower contamination of the sterile area; however, the recommended two methods required more time.

Disposable over Reusable Face Masks: Public Safety or Environmental Disaster?

Many governments have imposed the public use of face masks and they are now moving towards enforcing disposable masks to abate COVID-19 transmission. While disposable masks consistently provide higher protection, they also carry multiple environmental burdens, from greenhouse gases released during production to the landfilling and littering. Conversely, reusable masks’ protection can vary from >90% certified industrial masks, similar to disposable masks, to dubious homemade or artisanal masks. This work discusses the protection provided by different masks, their impact on the environment, and new proposals combining concerns about public health and sustainability.