N95 Respirators Research Articles

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

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

A Novel Antipathogenic Agent for Nonwoven Fabric

Medical-grade masks and N95 respirators containing non-woven fibers are designed to prevent the spread of airborne diseases. While they effectively trap respiratory droplets and aerosols, they cannot lyse entrapped pathogens. Embedded antimicrobial agents such as silver, copper, zinc, iodine, peptides, quaternary ammonium salts, or nanoparticles have been used to overcome this limitation. However, their effectiveness remains debatable because these materials can be toxins, allergens, irritants, and environmental hazards. Recently, silicon nitride (Si3N4) was found to be a potent antipathogenic compound, and it may be an ideal agent for masks. In powder or solid form, it is highly effective in inactivating bacteria, fungi, and viruses while leaving mammalian tissue unaffected. The purpose of this study was to serially assess the antiviral efficacy of Si3N4 against SARS-CoV-2 using powders, solids, and embedded nonwoven fabrics. Si3N4 powders and solids were prepared using conventional ceramic processing. The “pad-dry-cure” method was used to embed Si3N4 particles into polypropylene fibers. Fabric testing was subsequently conducted using industrial standards—ISO 18184 for antiviral effectiveness, ASTM F2299 and EN 13274-7 for filtration efficiency, EN 14683 for differential pressure drop, and ISO 18562-2 for particle shedding. A modification of ISO 18562-3 was also employed to detect ammonia release from the fabric. Antiviral effectiveness for Si3N4 powders, solids, and embedded fabrics were 99.99% at ≤ 5 min, ~ 93% in 24 h, and 87% to 92% in 120 min, respectively. Results of the standard mask tests were generally within prescribed safety limits. Further process optimization may lead to commercial Si3N4-based masks that not only “catch” but also “kill” pathogenic microbes.

Effect of N95 Respirator on Oxygen and Carbon Dioxide Physiologic Response: A Systematic Review and Meta-Analysis.

During the COVID-19 pandemic, N95 respirators were commonly used in many situations. Respiratory problems from prolonged use of respirators were discussed in many studies, which show varied results. From the inconclusive results, the current systematic review and meta-analysis discerned the effects of the N95 respirator by assessing the oxygen and carbon dioxide changes in both high- and low-to-moderate-intensity physical activities in a healthy population. Thirteen studies were identified for inclusion in the study. In high-intensity physical activities, our meta-analysis showed borderline lower oxygen saturation and higher carbon dioxide partial pressure, but oxygen saturation did not change in low-to-moderate physical activity. The use of N95 respirators could statistically affect the physiologic changes of carbon dioxide and oxygen in high-intensity physical activity among healthy participants, but this may not be clinically significant. Some users who have certain health conditions, such as respiratory problems, should be informed of the clinical symptoms related to hypercarbia and hypoxia for the early detection of adverse effects of N95 respirators.

Effect of UV-C germicidal irradiation (UVGI) on the structural integrity of N95 and KN95 respirators

This study focuses on reprocessing a group of filtering facepiece respirators (FFR) using ultraviolet germicidal irradiation (UVGI). The aim is to explore the possibility of disinfecting selected KN95 FFRs, in comparison with the N95 FFRs, and assess their viability for reusage. For this purpose, five models of unused N95 and KN95 FFR models obtained from the hospital were exposed to UV-C light using a customized UVGI chamber. The material integrity of treated FFRs was examined in terms of particle penetration and strap tension. The surface morphology of all models is inspected to determine the visible changes of each FFR upon exposure to 1–100 cycles (1 cycle is equivalent to 1 J/cm2 UV dose). The penetration test results indicate that the physical properties of the KN95 and N95 FFRs remain within permissible limits despite being reprocessed by up to 100 cycles (100 J/cm2). Using a microscope, the physical observations also reveal that no visible damage can be seen even after 100 J/cm2 exposure. Apart from the filter bodies, the tension of each strap was also found to not be significantly affected by UV radiation by at least 10 disinfection cycles (10 J/cm2). This confirms that KN95, as well as N95 FFRs, can be subjected to UV treatment as a means of disinfection.

Commercial Janus Fabrics as Reusable Facemask Materials: A Balance of Water Repellency, Filtration Efficiency, Breathability, and Reusability.

Facemasks as personal protective equipment play a significant role in helping prevent the spread of viruses during the COVID-19 pandemic. A desired reusable fabric facemask should strike a balance of water repellency, good filtration efficiency (FE), breathability, and mechanical robustness against washing cycles. Despite significant efforts in testing various commercial fabric materials for filtration efficiency, few have investigated fabric performance as a function of the fiber/yarn morphology and wettability of the fabric itself. In this study, we examine commercial fabrics with Janus-like behaviors to determine the best reusable fabric facemask materials by understanding the roles of morphology, porosity, and wettability of the fabric on its overall performance. We find that the outer layer of the diaper fabric consisted of laminated polyurethane, which is hydrophobic, has low porosity (∼5%) and tightly woven yarn structures, and shows the highest overall FE (up to 54%) in the submicron particle size range (0.03-0.6 μm) among the fabrics tested. Fabric layers with higher porosity lead to lower-pressure drops, indicating higher breathability but lower FE. Tightly woven waterproof rainwear fabrics perform the best after 10 washing cycles, remaining intact morphologically with only a 2-5% drop in the overall FE in the submicron particle size range, whereas other knitted fabric layers become loosened and the laminated polyurethane thin film on the diaper fabric is wrinkled. In comparison, the surgical masks and N95 respirators made from nonwoven polypropylene (PP) fibers see over a 30% decline in the overall FE after 10 washing cycles. Overall, we find that tightly woven Janus fabrics consisting of a low porosity, a hydrophobic outer layer, and a high porosity and hydrophilic inner layer offer the best performance among the fabrics tested as they can generate a high overall FE, achieve good breathability, and maintain fabric morphology and performance over multiple washing cycles.

Prevention of SARS-CoV-2 and respiratory viral infections in healthcare settings: current and emerging concepts.

COVID-19 has catalyzed a wealth of new data on the science of respiratory pathogen transmission and revealed opportunities to enhance infection prevention practices in healthcare settings. New data refute the traditional division between droplet vs airborne transmission and clarify the central role of aerosols in spreading all respiratory viruses, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), even in the absence of so-called 'aerosol-generating procedures' (AGPs). Indeed, most AGPs generate fewer aerosols than talking, labored breathing, or coughing. Risk factors for transmission include high viral loads, symptoms, proximity, prolonged exposure, lack of masking, and poor ventilation. Testing all patients on admission and thereafter can identify early occult infections and prevent hospital-based clusters. Additional prevention strategies include universal masking, encouraging universal vaccination, preferential use of N95 respirators when community rates are high, improving native ventilation, utilizing portable high-efficiency particulate air filters when ventilation is limited, and minimizing room sharing when possible. Multifaceted infection prevention programs that include universal testing, masking, vaccination, and enhanced ventilation can minimize nosocomial SARS-CoV-2 infections in patients and workplace infections in healthcare personnel. Extending these insights to other respiratory viruses may further increase the safety of healthcare and ready hospitals for novel respiratory viruses that may emerge in the future.

Filtration efficiency of N95 filtering facepiece respirators during multi-cycles of ‘8-hour simulated donning + disinfection’

BackgroundAerosol-borne diseases such as COVID-19 may outbreak occasionally in various regions of the world, inevitably resulting in short-term shortage and corresponding reuse of disposable respirators.AimTo investigate the effective disinfection methods, reusable duration and frequency of N95 respirators.MethodsBased on the self-built respirator simulation test system, and under combinations of experimental conditions of three N95 respirators × 0–200 nm NaCl aerosols × three simulated breathing flow rates (15, 50 and 85 L/min) × two disinfection methods (dry heating and ultraviolet (UV) radiation), this study continuously measured the changes in filtration efficiency of all respirators during multi-cycles of ‘8-h simulated donning + disinfection’ until the penetration reached ≥5%.FindingsMulti-cycles of dry heating and UV radiation treatments on the reused (i.e., multiple 8-h donning) N95 respirators had a minimal effect (<0.5%) on the respirator filtration efficiency, and even at 85 L/min, all tested N95 respirators were able to maintain filtration efficiencies ≥95% for at least 30 h or four reuse cycles of ‘8-h donning + disinfection’, while a lower breathing flow rate (15 L/min) plus the exhalation valve could further extend the N95 respirator's usability duration up to 140 h or 18 reuse cycles of ‘8-h donning + disinfection’. As the respirator wearing time extended, aerosol penetration slowly increased in a quadratic function with a negative second-order coefficient, and the penetration increment during each cycle of 8-h donning was less than 0.9%.ConclusionMulti-cycles of N95 respirator reuse in combination with dry heating or UV irradiation disinfection are feasible.

Effects of Long-Duration Wearing of Personal Protective Equipment with N95 Masks on Blood Oxygen Concentration and Pulse Rate Among Dental Professionals

Background: The importance of personal protective equipment (PPE) for health-care professionals working in an infective environment has been highlighted again in this COVID pandemic. CDC recommends the use of PPE with FFp2/N95 wear in dental health professionals. There are studies revealing the varied physiological as well as psychological impact of long-duration wear of PPE in health professionals. This study aims to evaluate the effects of wearing PPE with N95 mask before donning and after doffing (for 4 h) on the oxygen saturation levels and pulse rate. Materials and Methods: Forty dental surgeons of both sexes with informed consent working at a government dental college, in Kerala, were studied by a standard pulse oximetry test for oxygen saturation and pulse rate before donning and after doffing of PPE with FFP2/N95 respirator over 4 h duration. They were ensured to be hemodynamically stable, breathing room air under standard room temperature, and humidity. Data were entered and evaluated using a standard paired t-test using SPSS version 20. Results: The mean age group of the dental surgeons was 39 ± 9 years, and 60% were male. The mean values of oxygen saturation before donning and after doffing were 97.6 (1.1) and 96.7 (1.2), respectively, and the difference was significant (P &lt; 0.01). The pulse rate before donning and after doffing was found to be 79.7 (6.7) and 81.2 (6.7), respectively, with significance (P &lt; 0.01). However, the difference was not significant according to gender or age groups. Conclusion: The decrease in oxygen saturation and an increase in heart rate among dental surgeons were found to be significant after 4 h wear of PPE with FFP2 respirator. Nevertheless, these data of physiological impact of PPE cannot overshadow the risk-benefit ratio of PPE wear. The cautious use of PPE with improved technology can mitigate the risks involved in its use.

Effect of a Hydrogen Peroxide Gas-Plasma Sterilization on Physical Integrity and Quality of N95 Respirators

Background: N95 respirators have prevented transmission among health-care workers during the COVID-19 pandemic. During times of intense shortage of respirators and border closures during the pandemic, re-use strategies with available decontamination methods were necessitated. This in-house experimental study evaluated the effect of hydrogen peroxide gas-plasma sterilization on respirators and helped establish an evidence-based protocol for their re-use in a resource-poor setting. Materials and Methods: A three-dimensional experimental model using saline nebulization as the aerosol exposure and a particle counter to measure the filtration of particles through the mask pre- and post-sterilization was used. Multiple cycles of plasma sterilization were done till the physical integrity/fit was lost. Total filtration volume was used as a surrogate marker to assess the filtration efficiency (FE). Results: The total volume of particles filtered on a 3M respirator was 99.9%. Unused Halyard and Venus respirators were compared against 3M and found to have FE of 99.9% and 60.5%, respectively. After repeated sterilization cycles, the total volume of particles filtered was 59.3% for Halyard in the seventh cycle and 36.2% for Venus in the fifth cycle. When the physical integrity and fit was tested, the appropriate fit was lost after eight cycles of sterilization for Venus and was not lost for Halyard even after the tenth cycle. Conclusion: This low-cost experimental study helped implement an effective and safe decontamination strategy for safe re-use of N95 respirators in an emergent situation with no access to commercial testing in a resource poor health-care setting during the pandemic.

Letter to Editor

Letter to Editor

Prepare the psychiatric inpatient unit for COVID-19 pandemic.

Prepare the psychiatric inpatient unit for COVID-19 pandemic.

Personal protective equipment-related dermatoses in COVID-19 frontline health workers. A lesson learned from 1-year single center in the UAE.

Since COVID‐19 was declared a pandemic in March 2020, frontline health care workers wear personal protective equipment (PPE, surgical masks, N95 or similar respirators, gloves, goggles, face shields, and gowns). Alcohol‐based sanitizers and wipes were recommended. Such measures lead to disruption of the natural skin habitat and skin barrier and various cutaneous reactions. The aim was to assess the prevalence and characteristics of PPE‐related dermatoses among health care workers in Sheikh Khalifa Medical City (SKMC), a COVID‐19 facility, Abu Dhabi, United Arab Emirates. We conducted a voluntary, cross‐sectional anonymous survey among first‐line health care workers addressing types of PPE used, dermatoses classified as PPE related, and factors that influence them. Facial, nasal, and hand dermatoses were the most prevalent with 40.2%, 19.9%, and 14.1%, respectively. The changes are primarily attributed to surgical masks, N‐95 masks, and gloves. The shift duration is a contributing factor correlating with the severity of skin damage. Results of this study encouraged decision makers to recognize PPE‐related dermatoses as a continuously growing burden, reorganized the shift duration and PPE exposure, animated the personal to apply preventive measures, and promoted the well‐being of medical professionals in new waves of the pandemic.

SARS-CoV-2 exposures of healthcare workers from primary care, long-term care facilities and hospitals: a nationwide matched case-control study

ObjectivesThis study assessed the roles of various exposures and personal protective equipment (PPE) use on healthcare workers' (HCWs) risk of COVID-19 working in primary care, long-term-care facilities or hospitals. MethodsWe conducted a matched case-control (1:1) study (10 April through 9 July 2021). Cases (HCWs with confirmed COVID-19) and controls (HCWs without any COVID-19-positive test or symptoms) were invited by E-mail to complete an online questionnaire on their exposures and PPE use over the 10-day period preceding inclusion. Risk factors were analysed using multivariable conditional logistic regression. ResultsA total of 2076 cases and 2076 matched controls were included. The analysis retained exposure to an infected person outside work (adjusted OR 19.9 (95% CI, 12.4–31.9)), an infected colleague (OR 2.26 (95% CI, 1.53–3.33)) or COVID-19 patients (OR 2.37 (95% CI, 1.66–3.40)), as independent predictors of COVID-19 in HCWs, while partial (OR 0.30 (95% CI, 0.22–0.40)) or complete (OR 0.19 (95% CI, 0.14–0.27)) immunisation was protective. Eye protection (OR 0.57 (95% CI, 0.37–0.87)) and wearing a gown (OR 0.58 (95% CI, 0.34–0.97)) for COVID-19 patient care were protective, while wearing an apron slightly increased the risk of infection (OR 1.47 (95% CI, 1.00–2.18)). Protection of N95 respirators and surgical face masks did not differ. Compared to medical professions, being a nurse (OR 3.79 (95% CI, 2.50–5.76)) or a nurse's aide (OR 9.08 (95% CI, 5.30–15.5)) was associated with COVID-19. Results were consistent across all healthcare settings. DiscussionHCWs were more likely to get COVID-19 in their personal sphere than during occupational activities. Our results suggest that eye protection for HCWs during patient care should be actively promoted.

Real work experiences, practices and adverse events associated with long term usage of N95 respirators during the COVID-19 pandemic – A cross-sectional survey amongst Indian physicians

Introduction: Doctors are at increased risk of exposure to SARS-CoV-2 virus, and use of N95 respirators has emerged as a key preventive measure. This study aimed to study the real-world experiences, practices and adverse effects of N95 respirator usage amongst doctors of India. Methods: An analytical, cross-sectional online survey was conducted between November 2020 and January 2021. Real-world usage characteristics of N-95 respirators were collected via a pre-validated questionnaire (use, reuse, wearing and disposal practices) and compared amongst different sub-cohorts. Results: 453 responses from physicians were analyzed. The most important adjunct to the N95 respirator perceived by the respondents was the full-face shield (81.9%). Most doctors had to purchase extra mask per month (median = 5) and this was more amongst the medical specialties (p = 0.006). Highest mean VAS scores for adverse events were reported for breathing on exertion (6.62 ± 2.25) and ear pain (6.34 ± 2.69). VAS ear pain was higher in ages &lt; 40 and doctors working in the public sector (p = 0.017 and p = 0.019 respectively). Conclusion: There are many inadequacies with regard to proper mask removal and doffing techniques among doctors in India. The major adverse effects faced by the doctors on prolonged mask usage were ear pain and breathing on exertion. However, it can be noted in spite of these deficiencies; there is generally good adherence to protocols and good practices of mask usage in hospital setting.

Effect of Wearing N95 Mask on the Quality of Chest Compressions in Prehospital Emergency Personnel: A Cross-over Study

Objective To evaluate the effect of wearing an N95 mask on the quality of chest compression and fatigue of prehospital emergency personnel during cardiopulmonary resuscitation (CPR). Methods Twenty-four eligible participants were recruited. Participants' age, sex, height, and weight were recorded. After completing the CPR training and examination, participants were tested twice, wearing surgical mask or an N95 mask, while performing chest compressions for 2 minutes. The quality of chest compression (including compression frequency, depth, rebound, and position) was recorded by the simulator. Borg fatigue scores and physiological parameters (including heart rate, mean arterial pressure, pulse oxygen saturation, and respiratory rate) were recorded before and after chest compressions. Results Compared to wearing surgical masks, participants wearing N95 masks had significantly lower quality of chest compression, including compression frequency (98.3 ± 4.9 bpm vs 104.0 ± 6.0 bpm, P < 0.001), depth (47.1 ± 4.5 mm vs 50.5 ± 5.4 mm, P < 0.001), and rebound (90.2 ± 2.7% vs 94.3 ± 2.1%, P < 0.001). The compression position was not affected. The period data showed that the difference in compression quality started after 1 minute of compressions. Participants wearing N95 masks had higher Borg fatigue scores [6.1(2) vs 5.1(2), P < 0.001], heart rates (121.2 ± 5.7 bpm vs 109.9 ± 6.0 bpm, P < 0.001), mean arterial pressures (106.3 ± 8.0 mmHg vs 99.0 ± 8.5 mmHg, P = 0.012), and respiratory rates (29.5 ± 2.7 bpm vs 24.7 ± 2.5 bpm, P < 0.001). Conclusion This study showed that the use of an N95 mask by prehospital emergency personnel during the performance of chest compressions resulted in a reduction of compression quality and increased clinician fatigue. There is a need for CPR training for medical personnel wearing personal protective equipment.

Effect of Cloth Masks and N95 Respirators on Maximal Exercise Performance in Collegiate Athletes.

This study compared exercise performance and comfort while wearing an N95 filtering facepiece respirator (N95), cloth mask, or no intervention control for source control during a maximal graded treadmill exercise test (GXT). Twelve Division 1 athletes (50% female, age = 20.1 ± 1.2, BMI = 23.5 ± 1.6) completed GXTs under three randomized conditions (N95, cloth mask, control). GXT duration, heart rate (HR), respiration rate (RR), transcutaneous oxygen saturation (SpO2), transcutaneous carbon dioxide (TcPCO2), rating of perceived exertion (RPE), and perceived comfort were measured. Participants ran significantly longer in control (26.06 min) versus N95 (24.20 min, p = 0.03) or cloth masks (24.06 min, p = 0.04). No differences occurred in the slope of HR or SpO2 across conditions (p > 0.05). TcPCO2 decreased faster in control (B = −0.89) versus N95 (B = 0.14, p = 0.02) or cloth masks (B = −0.26, p = 0.03). RR increased faster in control (B = 8.32) versus cloth masks (B = 6.20, p = 0.04). RPE increased faster in the N95 (B = 1.91) and cloth masks (B = 1.79) versus control (B = 1.59, p < 0.001 and p = 0.05, respectively). Facial irritation/itching/pinching was higher in the N95 versus cloth masks, but sweat/moisture buildup was lower (p < 0.05 for all). Wearing cloth masks or N95s for source control may impact exercise performance, especially at higher intensities. Significant physiological differences were observed between cloth masks and N95s compared to control, while no physiological differences were found between cloth masks and N95s; however, comfort my differ.

The Effectiveness of Cipto Mangunkusumo Hospital Ultraviolet Germicidal Irradiation (UVGI) Chamber for N95 Respirators Disinfection in COVID-19 pandemics: A Preliminary Study

Introduction: During the COVID-19 pandemic, where the disease might spread in a medical facility setting, the common problems found in every country is the shortage of personal protective equipment (PPE) for medical personnel – especially the disposable N95 respirators. Thus, a higher amplitude to disinfect and reuse N95 is urgently needed. In this study, we designed an effective and safe disinfection methods through an Ultraviolet Germicidal Irradiation (UVGI) chamber in Dr. Cipto Mangunkusumo Hospital to control the shortage of PPE by disinfecting and reusing disposable N95 respirators. Purpose: To evaluate the dosage and effectiveness of UV-C radiation for disposable N95 respirators disinfection in our designated UVGI chamber. Methods: This study used a cross-sectional design to determine the dose and the effectiveness of UV-C radiation in eradicating SARS-CoV 2 on disposable N95 respirators. Results: Using two different distances from the light source, we confirmed the inverse square law of UV-C radiation power. Irradiation for 2 hours with a radiation dose of 1080 mJ/cm2 resulted in undetected SARS-CoV-2 gene based on PCR examination in 10 out of 10 samples. Conclusion: This UVGI chamber is a potential solution for hospitals or medical facilities to overcome the limitations that occurred in the pandemic by disinfecting PPE.

Decontamination Assessment of Nanofiber-based N95 Masks.

As the world battles with the outbreak of the novel coronavirus, it also prepares for future global pandemics that threaten our health, economy, and survivor. During the outbreak, it became evident that use of personal protective equipment (PPE), specially face masks, can significantly slow the otherwise uncontrolled spread of the virus. Nevertheless, the outbreak and its new variants have caused shortage of PPE in many regions of the world. In addition, waste management of the enormous economical and environmental footprint of single use PPE has proven to be a challenge. Therefore, this study advances the theme of decontaminating used masks. More specifically, the effect of various decontamination techniques on the integrity and functionality of nanofiber-based N95 masks (i.e. capable of at least filtering 95% of 0.3 μm aerosols) were examined. These techniques include 70% ethanol, bleaching, boiling, steaming, ironing as well as placement in autoclave, oven, and exposure to microwave (MW) and ultraviolet (UV) light. Herein, filtration efficiency (by Particle Filtration Efficiency equipment), general morphology, and microstructure of nanofibers (by Field Emission Scanning Electron microscopy) prior and after every decontamination technique were observed. The results suggest that decontamination of masks with 70% ethanol can lead to significant unfavorable changes in the microstructure and filtration efficiency (down to 57.33%) of the masks. In other techniques such as bleaching, boiling, steaming, ironing and placement in the oven, filtration efficiency dropped to only about 80% and in addition, some morphological changes in the nanofiber microstructure were seen. Expectedly, there was no significant reduction in filtration efficiency nor microstructural changes in the case of placement in autoclave and exposure to the UV light. It was concluded that, the latter methods are preferable to decontaminate nanofiber-based N95 masks.

N95 respirators for health care workers: the importance of fit, comfort, and usability

N95 respirators for health care workers: the importance of fit, comfort, and usability

Survey of coronavirus disease 2019 (COVID-19) infection control policies at leading US academic hospitals in the context of the initial pandemic surge of the severe acute respiratory coronavirus virus 2 (SARS-CoV-2) omicron variant.

To assess coronavirus disease 2019 (COVID-19) infection policies at leading US medical centers in the context of the initial wave of the severe acute respiratory coronavirus virus 2 (SARS-CoV-2) omicron variant. Electronic survey study eliciting hospital policies on masking, personal protective equipment, cohorting, airborne-infection isolation rooms (AIIRs), portable HEPA filters, and patient and employee testing. "Hospital epidemiologists from U.S. News top 20 hospitals and 10 hospitals in the CDC Prevention Epicenters program." As it is currently written, it implies all 30 hospitals are from the CDC Prevention Epicenters program, but that only applies to 10 hospitals. Alternatively, we could just say "Hospital epidemiologists from 30 leading US hospitals." Survey results were reported using descriptive statistics. Of 30 hospital epidemiologists surveyed, 23 (77%) completed the survey between February 15 and March 3, 2022. Among the responding hospitals, 18 (78%) used medical masks for universal masking and 5 (22%) used N95 respirators. 16 hospitals (70%) required universal eye protection. 22 hospitals (96%) used N95s for routine COVID-19 care and 1 (4%) reserved N95s for aerosol-generating procedures. 2 responding hospitals (9%) utilized dedicated COVID-19 wards; 8 (35%) used mixed COVID-19 and non-COVID-19 units; and 13 (57%) used both dedicated and mixed units. 4 hospitals (17%) used AIIRs for all COVID-19 patients, 10 (43%) prioritized AIIRs for aerosol-generating procedures, 3 (13%) used alternate risk-stratification criteria (not based on aerosol-generating procedures), and 6 (26%) did not routinely use AIIRs. 9 hospitals (39%) did not use portable HEPA filters, but 14 (61%) used them for various indications, most commonly as substitutes for AIIRs when unavailable or for specific high-risk areas or situations. 21 hospitals (91%) tested asymptomatic patients on admission, but postadmission testing strategies and preferred specimen sites varied substantially. 5 hospitals (22%) required regular testing of unvaccinated employees and 1 hospital (4%) reported mandatory weekly testing even for vaccinated employees during the SARS-CoV-2 omicron surge. COVID-19 infection control practices in leading hospitals vary substantially. Clearer public health guidance and transparency around hospital policies may facilitate more consistent national standards.