Estimating the reduction in SARS-CoV-2 viral load by common face masks with a simple leak model

Freitag, Steffen; Howell, S. G.; Jim, Kevin T. C.

doi:10.1080/02786826.2022.2053656

Cited by 5 publications

(4 citation statements)

References 67 publications

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“…The size distribution of the emitted droplets had a significant impact on the infection risk and on the evaluation of the protection provided by facemasks, as shown by a comparable model considering a slightly different emission size distribution. 124 As the amount of viral charges in a particle was considered to be mostly dependent on We aimed at taking into account the variability of the input parameters such as the total number of emitted droplets, the viral charge concentration and the infectivity (still under investigation for SARS-CoV-2 so far and highly dependent on new variants) and calculated infection risk distributions spanning over several orders of magnitude. We also based our calculations on estimated fit factors for the masks, intended to reflect the fitting qualities of FFP2 and medical masks worn by non-trained users.…”

Section: Limitati On S Of the De Veloped Modelmentioning

confidence: 99%

“…The size distribution of the emitted droplets had a significant impact on the infection risk and on the evaluation of the protection provided by facemasks, as shown by a comparable model considering a slightly different emission size distribution. 124 As the amount of viral charges in a particle was considered to be mostly dependent on the particle's volume, large particles can have a significant impact on the calculation of the infection risk and on the quantification of the mitigation role of facemasks. However, such particles are challenging to measure as they have substantial settling velocities, making them less likely to reach the sampling instruments.…”

Section: Limitations Of the Developed Modelmentioning

confidence: 99%

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

Wang

2022

Indoor Air

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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.

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Section: Limitati On S Of the De Veloped Modelmentioning

confidence: 99%

“…The size distribution of the emitted droplets had a significant impact on the infection risk and on the evaluation of the protection provided by facemasks, as shown by a comparable model considering a slightly different emission size distribution. 124 As the amount of viral charges in a particle was considered to be mostly dependent on the particle's volume, large particles can have a significant impact on the calculation of the infection risk and on the quantification of the mitigation role of facemasks. However, such particles are challenging to measure as they have substantial settling velocities, making them less likely to reach the sampling instruments.…”

Section: Limitations Of the Developed Modelmentioning

confidence: 99%

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

Wang

2022

Indoor Air

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“…Thus, highly populated indoor areas have caused a high number of infections. Nevertheless, studies have shown that masks prevent viruses from entering the airways in those areas in a high percentage [69,70].…”

Section: Virus Volume and Transmissionmentioning

confidence: 99%

Investigating the Role of Environmental Factors on the Survival, Stability, and Transmission of SARS-CoV-2, and Their Contribution to COVID-19 Outbreak: A Review

et al. 2022

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Studies conducted in the last four years show conflicting findings on the role of the environment in the survival, stability, and transmission of SARS-CoV-2. Based on the current evidence, the factors that affect the severity of COVID-19 include host interaction, environmental stability, virus volume, stability, transmission, social interactions, and restriction measures. Moreover, the persistence of the virus depends on different environmental conditions, videlicet temperature, humidity, pH, salinity, and solar radiation. The outbreak of respiratory viruses is related mainly to temperature and humidity, and geographical locations (latitude). In SARS-CoV-2, mainly temperature and humidity seem to play a fundamental role. Moreover, studies have indicated that social health factors such as equitable health systems, hygiene, and underlying diseases have played a pivotal role in the incidence and outbreak of COVID-19. Therefore, addressing health issues associated with reducing SARS-CoV-2 outbreaks plays an essential role in global health. In contrast, the environmental stimuli of the COVID-19 outbreak are mainly unknown. Given the ongoing threat of the COVID-19 pandemic, it is important to understand the stimuli to respond quickly to emerging SARS-CoV-2 variants while implementing long-term and sustainable control strategies. This review discusses the role of environmental factors and health conditions in the outbreak of SARS-CoV-2.

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“…Therefore, predicting or modeling the transmission of the virus is anything but accurate when accounting for a population wearing face masks. Researchers have then been interested in accounting for these leakages in their transmission models [33][34][35][36][37]. The use of computational models of the face, i.e., headform models, paired with computational fluid dynamics (CFD) or other physics models can be used to more accurately and systematically estimate the magnitude and location of the leakage sites for different face types.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Role of Face Shape on the Flow Dynamics and Effectiveness of Face Masks

Solano

Shoele

2022

Fluids

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Due to the COVID-19 pandemic, face masks have been used extensively in society. The effectiveness of face masks depends on their material, design, and fit. With much research being focused on quantifying the role of the material, the design and fit of masks have been an afterthought at most. Recent studies, on the other hand, have shown that the mask fit is a significant factor to consider when specifying the effectiveness of the face mask. Moreover, the fit is highly dependent on face topology. Differences in face types and anthropometrics lead to different face mask fit. Here, computational fluid dynamics simulations employing a novel model for porous membranes (i.e., masks) are used to study the leakage pattern of a cough through a face mask on different faces. The three faces studied (female, male, and child) are characteristic faces identified in a previous population study. The female face is observed to have the most leakage through the periphery of the mask, which results in the lowest fitted filtration efficiency of the three faces. The male and child faces had similar gap profiles, leakage and fitted filtration efficiencies. However, the flow of the three faces differs significantly. The effect of the porosity of the mask was also studied. While all faces showed the same general trend with changing porosity, the effect on the child’s face was more significant.

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Estimating the reduction in SARS-CoV-2 viral load by common face masks with a simple leak model

Cited by 5 publications

References 67 publications

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

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

Investigating the Role of Environmental Factors on the Survival, Stability, and Transmission of SARS-CoV-2, and Their Contribution to COVID-19 Outbreak: A Review

Investigation of the Role of Face Shape on the Flow Dynamics and Effectiveness of Face Masks

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