Adherence of SARS-CoV-2 delta variant to surgical mask and N95 respirators

The use of facial protection, including masks and respirators, has been adopted globally due to the COVID-19 pandemic. These products have been demonstrated to be effective in reducing the transmission of the virus. To determine whether or not the virus adheres to masks and respirators, we dissected four respirators and one surgical mask into layers. These individual layers were contaminated with the SARS-CoV-2 delta variant, and its release by vortexing was performed. Samples were used to infect Vero cells, and a plaque assay was used to determine to evaluate the adherence of the virus. Results showed that a cumulative log reduction of the layers reduced the load of the virus six-folds. Our study confirms the effectiveness of facial protection in reducing the transmission and or infection of the virus.

Dry heat sterilization as a method to recycle N95 respirator masks: The importance of fit

In times of crisis, including the current COVID-19 pandemic, the supply chain of filtering facepiece respirators, such as N95 respirators, are disrupted. To combat shortages of N95 respirators, many institutions were forced to decontaminate and reuse respirators. While several reports have evaluated the impact on filtration as a measurement of preservation of respirator function after decontamination, the equally important fact of maintaining proper fit to the users’ face has been understudied. In the current study, we demonstrate the complete inactivation of SARS-CoV-2 and preservation of fit test performance of N95 respirators following treatment with dry heat. We apply scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD) measurements, Raman spectroscopy, and contact angle measurements to analyze filter material changes as a consequence of different decontamination treatments. We further compared the integrity of the respirator after autoclaving versus dry heat treatment via quantitative fit testing and found that autoclaving, but not dry heat, causes the fit of the respirator onto the users face to fail, thereby rendering the decontaminated respirator unusable. Our findings highlight the importance to account for both efficacy of disinfection and mask fit when reprocessing respirators to for clinical redeployment.

Comparison of Effects of N95 Respirators and Surgical Masks to Physiological and Psychological Health among Healthcare Workers: A Randomized Controlled Trial

Since the onset of the coronavirus disease 2019 pandemic, wearing facemasks has become more important for healthcare workers. This study aimed to investigate and compare the influence of wearing N95 respirators and surgical masks for 8 h on physiological and psychological health. Sixty-eight healthcare workers were randomly assigned to the N95 respirator or surgical mask groups. Physiological parameters of participants were measured by Tensor Tip MTX at baseline and at the 2nd, 4th, 6th and 8th h of wearing the facemasks. The symptoms after wearing facemasks were also determined via the questionnaire. There were no significant changes in physiological parameters at most time checkpoints in both groups. Significant differences were observed in terms of heart rate at the 8th h, time trends (adjusted difference of least squares means were −8.53 and −2.01), and interaction of time and mask type between the two groups (p-value for interaction was 0.0146). The values of these physiological parameters were within normal ranges. The N95 respirator group had significantly higher incidences of shortness of breath, headache, dizziness, difficulty talking and fatigue that spontaneously resolved. In conclusion, healthcare workers who wore either N95 respirators or surgical masks during an 8 h shift had no obvious harmful effects on physiological and psychological health. Additionally, the N95 respirator group did not show a higher risk than the surgical mask group.

Breathing Uneasy: Fit-Tested N95 Respirator Access in Washington State Long-Term Care Facilities

Long-term care facilities (LTCF) have been disproportionately impacted by illness and death from COVID-19. Shortages of respirators for staff, especially Particulate Filtering Facepiece Respirators (N95), have limited LTCFs ability to follow public health recommendations for preventing COVID-19 transmission. Use of N95 respirators was infrequent in Washington State (WA) LTCFs prior to May 2020. N95 respirators must be individually fit tested to provide intended protection; a fit test is a procedure that tests the seal between the N95 respirator and the wearer’s face. The WA Department of Health (WA DOH), collaborated with stakeholders to survey LTCFs in November 2020 regarding needs for fit tested respirators and analyzed responses (n=384). Responses by facility type: 8.3% nursing homes, 17.7% assisted living, 62.8% adult family home, 11.2% other. In WA, adult family homes (AFH) are licensed for six or fewer residents. 23.70% of LTCFs indicated they did not have any N95 respirators in stock at their facility; 96.7% of these were AFH. In August 2020 WA DOH surveyed AFH owners and received 110 responses; 9.76% reported having at least one staff member fit tested for respirators. Smaller facilities may experience increased burden in accessing N95 respirators and fit testing due to lack of established relationships with suppliers and small volumes being purchased. WA DOH used federal COVID funding to contract with mobile fit testing providers and prioritized AFHs for this service. Between December 1, 2020-February 28, 2021, staff at 290 LTCFs were fit tested. The project will continue throughout 2021.

Moldable Mask: A Reusable, Hot Water Moldable, Additively Manufactured Mask to Be Used as an N95 Alternative

There has been high demand for personal protective equipment (PPE) during the COVID-19 pandemic, especially N95 respirators. Unfortunately, at the early stage of the pandemic, the supply could not meet the demand for N95 respirators, leading to a shortage and unsafe reuse of this form of PPE. We developed the Moldable Mask to ease the demand for N95 respirators by creating a 3D-printed mask that uses a piece of N95 material as a filter. A sheet of N95 material could be used or one N95 respirator to be turned into two masks. The main feature of the mask is the ability to easily mold it in hot water to create a custom fit for each user. It can also be easily assembled at home with affordable materials. The final mask design was qualitatively fit tested on 13 subjects, with all subjects showing an improvement in fit with the hot water molding technique and 10 (77%) subjects passing the fit test. This shows that the Moldable Mask is a viable option for a safe, affordable N95 alternative when N95 mask supply is strained.

Validation of N95 respirator mask for the Re-use in the pandemic crisis

The SARS COVID 19 (Severe Acute Respiratory Syndrome Corona Virus Disease 2019) pandemic has created a surge in the need for N95 respirators all across the world. Health care systems are struggling to find a way to cleanse and decontaminate the N95 masks for reuse. To combat the crisis there is a need to validate the N95 mask for efficiency and air filterability on repeated exposure to UV irradiation and vaporized hydrogen peroxide with equal parts of normal saline. To validate N95 respirator mask by using UVGI (Ultra Violet Germicidal Irradiation) method using UV hood and VHP (Vaporized Hydrogen peroxide 6% with equal volume saline 0.9% using an OT fogger machine). VHP decontamination is the method of choice to repeatedly re-sterilize N95 masks. Decontamination by the VHP method is more efficient in killing microorganisms within a short duration of exposure (60 minutes). The method retains the texture of the mask material, re-usability and air filterability even with repeated exposure (up to 10 times). UVGI does sterilize the mask but is inferior to VHP in retaining air filterability.

Decontamination Methods of N95 Respirators Contaminated with SARS-CoV-2

In the preparation and response to the COVID-19 pandemic, a sufficient supply of personal protective equipment (PPE), particularly the face mask, is essential. Shortage of PPE due to growing demand leaves health workers at significant risk as they fight this pandemic on the frontline. As a mitigation measure to overcome potential mask shortages, these masks could be decontaminated and prepared for reuse. This review explored past scientific research on various methods of decontamination of the N95-type respirators and their efficiency against the SARS-CoV-2 virus. Ultraviolet germicidal irradiation (UVGI) and hydrogen peroxide vapor (HPV) show great potential as an effective decontamination system. In addition, UVGI and HPV exhibit excellent effectiveness against the SARS-CoV-2 virus on the N95 respirator surfaces.

Systematic experimental comparison of particle filtration efficiency test methods for commercial respirators and face masks

Respirators, medical masks, and barrier face coverings all filter airborne particles using similar physical principles. However, they are tested for certification using a variety of standardized test methods, creating challenges for the comparison of differently certified products. We have performed systematic experiments to quantify and understand the differences between standardized test methods for N95 respirators (NIOSH TEB-APR-STP-0059 under US 42 CFR 84), medical face masks (ASTM F2299/F2100), and COVID-19-related barrier face coverings (ASTM F3502-21). Our experiments demonstrate the role of face velocity, particle properties (mean size, size variability, electric charge, density, and shape), measurement techniques, and environmental preconditioning. The measured filtration efficiency was most sensitive to changes in face velocity and particle charge. Relative to the NIOSH method, users of the ASTM F2299/F2100 method have commonly used non-neutralized (highly charged) aerosols as well as smaller face velocities, each of which may result in approximately 10% higher measured filtration efficiencies. In the NIOSH method, environmental conditioning at elevated humidity increased filtration efficiency in some commercial samples while decreasing it in others, indicating that measurement should be performed both with and without conditioning. More generally, our results provide an experimental basis for the comparison of respirators certified under various international methods, including FFP2, KN95, P2, Korea 1st Class, and DS2.