Of masks and methylene blue-The use of methylene blue photochemical treatment to decontaminate surgical masks contaminated with a tenacious small nonenveloped norovirus.

BACKGROUND: In the context of the SARS-CoV-2 pandemic, reuse of personal protective equipment, specifically that of medical face coverings, has been recommended. The reuse of these typically single-use only items necessitates procedures to inactivate contaminating human respiratory and gastrointestinal pathogens. We previously demonstrated decontamination of surgical masks and respirators contaminated with infectious SARS-CoV-2 and various animal coronaviruses via low concentration- and short exposure methylene blue photochemical treatment (10 µM methylene blue, 30 minutes of 12,500-lux red light or 50,000 lux white light exposure). METHODS: Here, we describe the adaptation of this protocol to the decontamination of a more resistant, non-enveloped gastrointestinal virus and demonstrate efficient photodynamic inactivation of murine norovirus, a human norovirus surrogate. RESULTS: Methylene blue photochemical treatment (100 µM methylene blue, 30 minutes of 12,500-lux red light exposure) of murine norovirus-contaminated masks reduced infectious viral titers by over four orders of magnitude on surgical mask surfaces. DISCUSSION AND CONCLUSIONS: Inactivation of a norovirus, the most difficult to inactivate of the respiratory and gastrointestinal human viruses, can predict the inactivation of any less resistant viral mask contaminant. The protocol developed here thus solidifies the position of methylene blue photochemical decontamination as an important tool in the package of practical pandemic preparedness.

Unfolding the effects of decontamination treatments on the structural and functional integrity of N95 respirators via numerical simulations.

Filtering facepiece respirators (FFRs) provide effective protection against diseases spread through airborne infectious droplets and particles. The widespread use of FFRs during the COVID-19 pandemic has not only led to supply shortages, but the disposal of single-use facemasks also threatens the environment with a new kind of plastic pollution. While limited reuse of filtering facepiece respirators has been permitted as a crisis capacity strategy, there are currently no standard test methods available for decontamination before their repeated use. The decontamination of respirators can compromise the structural and functional integrity by reducing the filtration efficiency and breathability. Digital segmentation of X-ray microcomputed tomography (microCT) scans of the meltblown nonwoven layers of a specific N95 respirator model (Venus-4400) after treatment with one and five cycles of liquid hydrogen peroxide, ultraviolet radiation, moist heat, and aqueous soap solution enabled us to perform filtration simulations of decontaminated respirators. The computed filtration efficiencies for 0.3 µm particles agreed well with experimental measurements, and the distribution of particle penetration depths was correlated with the structural changes resulting from decontamination. The combination of X-ray microCT imaging with numerical simulations thus provides a strategy for quantitative evaluation of the effectiveness of decontamination treatments for a specific respirator model.

Towards the direct detection of viral materials at the surface of protective face masks via infrared spectroscopy.

The ongoing COVID-19 pandemic represents a considerable risk for the general public and especially for health care workers. To avoid an overloading of the health care system and to control transmission chains, the development of rapid and cost-effective techniques allowing for the reliable diagnosis of individuals with acute respiratory infections are crucial. Uniquely, the present study focuses on the development of a direct face mask sampling approach, as worn (i.e., used) disposable face masks contain exogenous environmental constituents, as well as endogenously exhaled breath aerosols. Optical techniques-and specifically infrared (IR) molecular spectroscopic techniques-are promising tools for direct virus detection at the surface of such masks. In the present study, a rapid and non-destructive approach for monitoring exposure scenarios via medical face masks using attenuated total reflection infrared spectroscopy is presented. Complementarily, IR external reflection spectroscopy was evaluated in comparison for rapid mask analysis. The utility of a face mask-based sampling approach was demonstrated by differentiating water, proteins, and virus-like particles sampled onto the mask. Data analysis using multivariate statistical algorithms enabled unambiguously classifying spectral signatures of individual components and biospecies. This approach has the potential to be extended towards the rapid detection of SARS-CoV-2-as shown herein for the example of virus-like particles which are morphologically equivalent to authentic virus-without any additional sample preparation or elaborate testing equipment at laboratory facilities. Therefore, this strategy may be implemented as a routine large-scale monitoring routine, e.g., at health care institutions, nursing homes, etc. ensuring the health and safety of medical personnel.

Effectiveness of face masks in blocking the transmission of SARS-CoV-2: A preliminary evaluation of masks used by SARS-CoV-2-infected individuals.

In 2019, a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is transmitted via the airborne route, caused a new pandemic namely, "coronavirus disease 2019" (COVID-19). Although the effectiveness of face masks to prevent the transmission of SARS-CoV-2 is debated, no study has evaluated the virus-blocking efficacy of masks used by patients. We aimed to evaluate this efficacy of masks used by SARS-CoV-2-infected individuals. Data, masks used, and nasopharyngeal swab samples were obtained from these patients. Forty-five paired samples of nasopharyngeal swabs and masks were obtained and processed; the majority of masks were woven. Viral RNAs were amplified using quantitative reverse-transcription polymerase chain reaction and detected only on the inner parts of masks. Median viral load (VL) values of swabs and masks were 1.954x106 and 2,51x103, respectively. Statistically, there was a difference of approximately 1000 RNA copies/mL between swabs and masks and no significant difference in VL values among different types of masks. There were statistically significant differences in VL values between men and women and between symptomatic and asymptomatic patients. Our findings suggest the blocking of virus transmission by different types of masks and reinforce the use of masks by both infected and non-infected individuals.

Case study: risk associated to wearing silver or graphene nanoparticle-coated facemasks for protection against COVID-19.

The world is living a pandemic situation derived from the worldwide spreading of SARS-CoV-2 virus causing COVID-19. Facemasks have proven to be one of the most effective prophylactic measures to avoid the infection that has made that wearing of facemasks has become mandatory in most of the developed countries. Silver and graphene nanoparticles have proven to have antimicrobial properties and are used as coating of these facemasks to increase the effectivity of the textile fibres. In the case of silver nanoparticles, we have estimated that in a real scenario the systemic (internal) exposure derived from wearing these silver nanoparticle facemasks would be between 7.0 × 10-5 and 2.8 × 10-4 mg/kg bw/day. In addition, we estimated conservative systemic no effect levels between 0.075 and 0.01 mg/kg bw/day. Therefore, we estimate that the chronic exposure to silver nanoparticles derived form facemasks wearing is safe. In the case of graphene, we detected important gaps in the database, especially regarding toxicokinetics, which prevents the derivation of a systemic no effect level. Nevertheless, the qualitative approach suggests that the risk of dermal repeated exposure to graphene is very low, or even negligible. We estimated that for both nanomaterials, the risk of skin sensitisation and genotoxicity is also negligible.

Impact of COVID-19 in Immunosuppressed Children With Neuroimmunologic Disorders.

BACKGROUND AND OBJECTIVES: To investigate whether children receiving immunosuppressive therapies for neuroimmunologic disorders had (1) increased susceptibility to SARS-CoV2 infection or to develop more severe forms of COVID-19; (2) increased relapses or autoimmune complications if infected; and (3) changes in health care delivery during the pandemic. METHODS: Patients with and without immunosuppressive treatment were recruited to participate in a retrospective survey evaluating the period from March 14, 2020, to March 30, 2021. Demographics, clinical features, type of immunosuppressive treatment, suspected or confirmed COVID-19 in the patients or cohabitants, and changes in care delivery were recorded. RESULTS: One hundred fifty-three children were included: 84 (55%) female, median age 13 years (interquartile range [8-16] years), 79 (52%) on immunosuppressive treatment. COVID-19 was suspected or confirmed in 17 (11%) (all mild), with a frequency similar in patients with and without immunosuppressive treatment (11/79 [14%] vs 6/74 [8%], p = 0.3085). The frequency of neurologic relapses was similar in patients with (18%) and without (21%) COVID-19. Factors associated with COVID-19 included having cohabitants with COVID-19 (p < 0.001) and lower blood levels of vitamin D (p = 0.039). Return to face-to-face schooling or mask type did not influence the risk of infection, although 43(28%) children had contact with a classmate with COVID-19. Clinic visits changed from face to face to remote for 120 (79%) patients; 110 (92%) were satisfied with the change. DISCUSSION: In this cohort of children with neuroimmunologic disorders, the frequency of COVID-19 was low and not affected by immunosuppressive therapies. The main risk factors for developing COVID-19 were having cohabitants with COVID-19 and low vitamin D levels.

SARS-CoV2 neutralizing activity of ozone on porous and non-porous materials.

The COVID-19 pandemic has generated a major need for non-destructive and environmentally friendly disinfection methods. This work presents the development and testing of a disinfection process based on gaseous ozone for SARS-CoV-2-contaminated porous and non-porous surfaces. A newly developed disinfection chamber was used, equipped with a CeraPlas™ cold plasma generator that produces ozone during plasma ignition. A reduction of more than log 6 of infectious virus could be demonstrated for virus-contaminated cotton and FFP3 face masks as well as glass slides after exposure to 800 ppm ozone for 10-60 min, depending on the material. In contrast to other disinfectants, ozone can be produced quickly and cost-effectively, and its environmentally friendly breakdown product oxygen does not leave harmful residues. Disinfection with ozone could help to overcome delivery difficulties of personal protective equipment by enabling safe reuse with further applications, thereby reducing waste generation, and may allow regular disinfection of personal items with non-porous surfaces.

Adaptação cultural e validação da reason of using face masks cale para brasileiros / Adaptación cultural y validación de la reason of using face mask scale para brasileños / Cultural adaptation and validation of the reason of using face mask scale for brazilians

RESUMO Objetivo: realizar a tradução, adaptação cultural e validação da Reason of Using Face Mask Scale entre brasileiros. Métodos: estudo metodológico realizado entre abril e maio de 2020 mediante as seguintes etapas: tradução; síntese das traduções; retrotradução; comitê de juízes; pré-teste e avaliação das propriedades psicométricas. A coleta dos dados foi online a partir de mensagens enviadas por meio de mídias sociais. O questionário foi disponibilizado a partir de um link e os dados armazenados no Google Forms. Utilizou-se a Análise Fatorial Exploratória, testes de Kaiser-Meyer-Olkin e de Esfericidade de Bartlett para constatar se a amostra era adequada e passível de fatoração. Resultados: a escala foi traduzida para o português, avaliada por cinco especialistas, pré-testada com 20 adultos e aplicada em 500 pessoas da população brasileira. O índice de validade de conteúdo para a escala como um todo foi de 0,92. Os valores de Kaiser-Meyer-Olkin (0,639) e teste de esfericidade de Bartlett (p=0,000) indicaram que os itens eram fatoráveis. A variância explicada foi de 62,18%. Na validade de construto por grupos distintos, obteve-se resultado satisfatório (p<0,05). Conclusão: a Versão Brasileira da escalafoi adaptada para a cultura brasileira, sendo válida para avaliar os motivos para o uso de máscaras entre brasileiros.

RESUMEN Objetivo: realizar la traducción, adaptación cultural y validación de la Reason ofUsingFaceMaskScale entre brasileños. Métodos: estudio metodológico realizado entre abril y mayo de 2020 a través de las siguientes etapas: traducción; síntesis de las traducciones; retrotraducción; evaluación por jueces; pretest y evaluación de las propiedades psicométricas. La recolección de datos se realizó online a partir de mensajes enviados a través de redes sociales. La encuesta se hizo disponible a partir de un enlace y los datos almacenados en Google Forms. Se utilizó el Análisis Factorial Exploratorio, pruebas de Kaiser-Meyer-Olkin y de Esfericidad de Bartlett para determinar si la muestra era adecuada y susceptible a la factorización. Resultados: la escala fue traducida al portugués, evaluada por cinco especialistas, pre-testada con 20 adultos y aplicada en 500 personas de la población brasileña. El índice de validez del contenido para la escala como un todo fue de 0,92. Los valores de Kaiser-Meyer-Olkin (0,639) y test de esfericidad de Bartlett (p=0,000) indicaron que los ítems eran susceptibles a la factorización. La varianza explicada fue de 62,18%. En la validez de constructo por grupos distintos se obtuvo resultado satisfactorio (p<0,05). Conclusión: la Versión Brasileña de la escala fue adaptada para la cultura brasileña yes válida para evaluar los motivos para el uso de máscaras entre brasileños.

ABSTRACT Objective: to carry out the translation, cultural adaptation and validation of the Reason of Using Face Mask Scale among Brazilians. Methods: methodological study conducted between April and May 2020 using the following steps: translation; synthesis of translations; back-translation; committee of judges; pre-test and evaluation of psychometric properties. Data collection took place online from messages sent through social media. The questionnaire was made available from a link and the data stored in Google Forms. Exploratory Factor Analysis, Kaiser-Meyer-Olkin and Bartlett's Sphericity tests were used to check if the sample was adequate and factorable. Results: the scale was translated into Portuguese, evaluated by five experts, pre-tested with 20 adults and applied to 500 people from the Brazilian population. The content validity index for the scale as a whole was 0.92. The Kaiser-Meyer-Olkin (0.639) and Bartlett's Sphericity test (p=0.000) values indicated that the items were factorable. The explained variance was 62.18%. In the construct validity for different groups, a satisfactory result was obtained (p<0.05). Conclusion: the Brazilian Version of the scale was adapted to the Brazilian culture and is valid to evaluate the reasons for the use of masks among Brazilians.

Durable nanocomposite face masks with high particulate filtration and rapid inactivation of coronaviruses.

The COVID-19 pandemic presents a unique challenge to the healthcare community due to the high infectivity rate and need for effective personal protective equipment. Zinc oxide nanoparticles have shown promising antimicrobial properties and are recognized as a safe additive in many food and cosmetic products. This work presents a novel nanocomposite synthesis approach, which allows zinc oxide nanoparticles to be grown within textile and face mask materials, including melt-blown polypropylene and nylon-cotton. The resulting nanocomposite achieves greater than 3 log10 reduction (≥ 99.9%) in coronavirus titer within a contact time of 10 min, by disintegrating the viral envelope. The new nanocomposite textile retains activity even after 100 laundry cycles and has been dermatologist tested as non-irritant and hypoallergenic. Various face mask designs were tested to improve filtration efficiency and breathability while offering antiviral protection, with Claros' design reporting higher filtration efficiency than surgical masks (> 50%) for particles ranged 200 nm to 5 µm in size.

An upper bound on one-to-one exposure to infectious human respiratory particles.

There is ample evidence that masking and social distancing are effective in reducing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. However, due to the complexity of airborne disease transmission, it is difficult to quantify their effectiveness, especially in the case of one-to-one exposure. Here, we introduce the concept of an upper bound for one-to-one exposure to infectious human respiratory particles and apply it to SARS-CoV-2. To calculate exposure and infection risk, we use a comprehensive database on respiratory particle size distribution; exhalation flow physics; leakage from face masks of various types and fits measured on human subjects; consideration of ambient particle shrinkage due to evaporation; and rehydration, inhalability, and deposition in the susceptible airways. We find, for a typical SARS-CoV-2 viral load and infectious dose, that social distancing alone, even at 3.0 m between two speaking individuals, leads to an upper bound of 90% for risk of infection after a few minutes. If only the susceptible wears a face mask with infectious speaking at a distance of 1.5 m, the upper bound drops very significantly; that is, with a surgical mask, the upper bound reaches 90% after 30 min, and, with an FFP2 mask, it remains at about 20% even after 1 h. When both wear a surgical mask, while the infectious is speaking, the very conservative upper bound remains below 30% after 1 h, but, when both wear a well-fitting FFP2 mask, it is 0.4%. We conclude that wearing appropriate masks in the community provides excellent protection for others and oneself, and makes social distancing less important.

New novel thermal insulation and sound-absorbing materials from discarded facemasks of COVID-19 pandemic.

Due to the COVID-19 pandemic, people were encouraged and sometimes required to wear disposable facemasks, which then are discarded creating an environmental problem. In this study, we aim at investigating novel ideas to recycle wasted facemasks in order to lower the environmental impact. An experimental study has been carried out to investigate the possibility of using discarded masks for thermal insulation and sound absorption. The wasted masks are simulated by new masks, which stripped off the nose clips, elastic ear loops and are heated to 120 °C for one hour to kill any biological contaminants. The masks are also melted to investigate their thermal insulation and sound absorption properties. Results show that the thermal conductivity coefficients of the loose and melted masks are 0.03555 and 0.08683 W/m K, respectively, at room temperature of about 25 °C. Results show also that the sound absorption coefficient for loose masks is above 0.6 for the frequency range 600-5000 Hz. The loose facemasks are found to be thermally stable up to 295 °C, elastic ear loops at 304.7 °C, and the composite (melted) facemasks at 330.0 °C using the thermo-gravimetric analysis. Characterization of the facemask's three-layer fibers and the composite (melted) samples is obtained using scanning electron microscopy (SEM). The three-point bending test is obtained for the composite specimens showing good values of flexural stress, flexural strain, and flexural elastic modulus. These results are promising about using such discarded masks as new thermal insulation and sound-absorbing materials for buildings replacing the synthetic or petrochemical insulation materials.

The properties of hot household hygroscopic materials and their potential use for non-medical facemask decontamination.

The widespread use of facemasks throughout the population is recommended by the WHO to reduce transmission of the SARS-CoV-2 virus. As some regions of the world are facing mask shortages, reuse may be necessary. However, used masks are considered as a potential hazard that may spread and transmit disease if they are not decontaminated correctly and systematically before reuse. As a result, the inappropriate decontamination practices that are commonly witnessed in the general public are challenging management of the epidemic at a large scale. To achieve public acceptance and implementation, decontamination procedures need to be low-cost and simple. We propose the use of hot hygroscopic materials to decontaminate non-medical facemasks in household settings. We report on the inactivation of a viral load on a facial mask exposed to hot hygroscopic materials for 15 minutes. As opposed to recent academic studies whereby decontamination is achieved by maintaining heat and humidity above a given value, a more flexible procedure is proposed here using a slow decaying pattern, which is both effective and easier to implement, suggesting straightforward public deployment and hence reliable implementation by the population.

Metal leaching from antimicrobial cloth face masks intended to slow the spread of COVID-19.

Global health organizations recommend the use of cloth face coverings to slow the spread of COVID-19. Seemingly overnight, companies whose primary business is in no way related to healthcare or personal protective equipment-from mattresses manufacturers to big box stores-transitioned into the "mask business." Many companies advertise antimicrobial masks containing silver, copper, or other antimicrobials. Often, the techniques used to load such antimicrobials onto mask fibers are undisclosed, and the potential for metal leaching from these masks is yet unknown. We exposed nine so-called "antimicrobial" face masks (and one 100% cotton control mask) to deionized water, laundry detergent, and artificial saliva to quantify the leachable silver and copper that may occur during mask washing and wearing. Leaching varied widely across manufacturer, metal, and leaching solution, but in some cases was as high as 100% of the metals contained in the as-received mask after 1 h of exposure.

Respiratory virus deterrence induced by modified mask filter.

Airborne transmission of infectious respiratory pathogens is a significant health hazard for the general public as well as healthcare professionals. Face masks have been frequently utilized as safety measures to limit the transmission of these infectious aerosolized particles. However, the efficacy of face masks in reducing respiratory virus infectivity and pathogenicity is unknown. Improving the effectiveness of masks in blocking viruses is urgently needed. In this study, surgical mask filters were modified by coating the filters with 1, 3, or 5 M of sodium dihydrogen phosphate, and subsequently exposed to the aerosolized respiratory influenza viruses (A/H3N2, A/H5N1) generated by a nebulizer set. Mask filter modification significantly reduced the size and counts of filter pores, which enabled entrapment of 40-60% of aerosolized viruses (captured viruses) with more than 90% of the captured viruses losing their infectivity. Upon contact with the coated mask filters, both the captured viruses and the viruses that managed to bypass the filter pore (passed viruses) were found to be inactivated. Passed viruses demonstrated significantly reduced pathogenicity in mice as indicated by significantly reduced lung virus titers, bodyweight loss, and prolonged survival compared to bare control. These findings highlight the potential of modified mask filters for reducing viral activity and pathogenicity, which contributes to improving facial mask efficacy as well as limiting airborne pathogen transmission.

The social amplification and attenuation of COVID-19 risk perception shaping mask wearing behavior: A longitudinal twitter analysis.

INTRODUCTION: Twitter represents a mainstream news source for the American public, offering a valuable vehicle for learning how citizens make sense of pandemic health threats like Covid-19. Masking as a risk mitigation measure became controversial in the US. The social amplification risk framework offers insight into how a risk event interacts with psychological, social, institutional, and cultural communication processes to shape Covid-19 risk perception. METHODS: Qualitative content analysis was conducted on 7,024 mask tweets reflecting 6,286 users between January 24 and July 7, 2020, to identify how citizens expressed Covid-19 risk perception over time. Descriptive statistics were computed for (a) proportion of tweets using hyperlinks, (b) mentions, (c) hashtags, (d) questions, and (e) location. RESULTS: Six themes emerged regarding how mask tweets amplified and attenuated Covid-19 risk: (a) severity perceptions (18.0%) steadily increased across 5 months; (b) mask effectiveness debates (10.7%) persisted; (c) who is at risk (26.4%) peaked in April and May 2020; (d) mask guidelines (15.6%) peaked April 3, 2020, with federal guidelines; (e) political legitimizing of Covid-19 risk (18.3%) steadily increased; and (f) mask behavior of others (31.6%) composed the largest discussion category and increased over time. Of tweets, 45% contained a hyperlink, 40% contained mentions, 33% contained hashtags, and 16.5% were expressed as a question. CONCLUSIONS: Users ascribed many meanings to mask wearing in the social media information environment revealing that COVID-19 risk was expressed in a more expanded range than objective risk. The simultaneous amplification and attenuation of COVID-19 risk perception on social media complicates public health messaging about mask wearing.

Feasibility and utility of facemask sampling in the detection of SARS-CoV-2 during an ongoing pandemic.

Easy access to screening for timely identification and isolation of infectious COVID-19 patients remains crucial in sustaining the international efforts to control COVID-19 spread. A major barrier limiting broad-based screening is the lack of a simple, rapid, and cost-effective COVID-19 testing method. We evaluated the feasibility and utility of facemask sampling in a cohort of 42 COVID-19-positive and 36 COVID-19-negative patients. We used a prototype of Steri-Strips™ (3 M) applied to the inner surface of looped surgical facemasks (Assure), which was worn by patients for a minimum wear time of 3 h, then removed and sent for SARS-CoV-2 PCR testing. Baseline demographics and symptomatology were also collected. Facemask sampling positivity was highest within the first 5 days of symptomatic presentation. Patients with nasopharyngeal and/or oropharyngeal swab SARS-CoV-2 PCR Ct values < 25.09 had SARS-CoV-2 detected on facemask sampling, while patients with Ct values ≥ 25.2 had no SARS-CoV-2 detected on facemask sampling. Facemask sampling can identify patients with COVID-19 during the early symptomatic phase or those with high viral loads, hence allowing timely identification and isolation of those with the highest transmission risk. Given the widespread use of facemasks, this method can potentially be easily applied to achieve broad-based, or even continuous, population screening.

UV decontamination of personal protective equipment with idle laboratory biosafety cabinets during the COVID-19 pandemic.

Personal protective equipment (PPE) is crucially important to the safety of both patients and medical personnel, particularly in the event of an infectious pandemic. As the incidence of Coronavirus Disease 2019 (COVID-19) increases exponentially in the United States and many parts of the world, healthcare provider demand for these necessities is currently outpacing supply. In the midst of the current pandemic, there has been a concerted effort to identify viable ways to conserve PPE, including decontamination after use. In this study, we outline a procedure by which PPE may be decontaminated using ultraviolet (UV) radiation in biosafety cabinets (BSCs), a common element of many academic, public health, and hospital laboratories. According to the literature, effective decontamination of N95 respirator masks or surgical masks requires UV-C doses of greater than 1 Jcm-2, which was achieved after 4.3 hours per side when placing the N95 at the bottom of the BSCs tested in this study. We then demonstrated complete inactivation of the human coronavirus NL63 on N95 mask material after 15 minutes of UV-C exposure at 61 cm (232 µWcm-2). Our results provide support to healthcare organizations looking for methods to extend their reserves of PPE.

The SARS-CoV-2 viral load in COVID-19 patients is lower on face mask filters than on nasopharyngeal swabs.

Face masks and personal respirators are used to curb the transmission of SARS-CoV-2 in respiratory droplets; filters embedded in some personal protective equipment could be used as a non-invasive sample source for applications, including at-home testing, but information is needed about whether filters are suited to capture viral particles for SARS-CoV-2 detection. In this study, we generated inactivated virus-laden aerosols of 0.3-2 microns in diameter (0.9 µm mean diameter by mass) and dispersed the aerosolized viral particles onto electrostatic face mask filters. The limit of detection for inactivated coronaviruses SARS-CoV-2 and HCoV-NL63 extracted from filters was between 10 to 100 copies/filter for both viruses. Testing for SARS-CoV-2, using face mask filters and nasopharyngeal swabs collected from hospitalized COVID-19-patients, showed that filter samples offered reduced sensitivity (8.5% compared to nasopharyngeal swabs). The low concordance of SARS-CoV-2 detection between filters and nasopharyngeal swabs indicated that number of viral particles collected on the face mask filter was below the limit of detection for all patients but those with the highest viral loads. This indicated face masks are unsuitable to replace diagnostic nasopharyngeal swabs in COVID-19 diagnosis. The ability to detect nucleic acids on face mask filters may, however, find other uses worth future investigation.

Anti-SARS-CoV-2 Activity of Surgical Masks Infused with Quaternary Ammonium Salts.

The SARS-CoV-2 pandemic has highlighted the need for protective and effective personal protective equipment (PPE). Research has shown that SARS-CoV-2 can survive on personal protective equipment, such as commonly used surgical masks. Methods are needed to inactivate virus on contaminated material. We show here that embedding viral-disinfecting compounds during the manufacturing of surgical masks inactivates a high dose (up to 1 × 105 pfu) of live, authentic SARS-CoV-2 within minutes.