The experiments were repeated three times ( n = 3). Data are presented as means ± standard deviations (SD). Triangles in panel I indicate that the value was below the detection limit. The numbers below the bars show the percentages relative to the leftmost control bar values. The brown bars and dots and the y axis on the right show the copy numbers of viral RNA. The blue bars and dots and the y axis on the left show virus titers. The N95 masks were evaluated using the following two conditions: the mask fit naturally along the contours of the mannequin’s head, or the edges of the N95 masks were sealed with adhesive tape. Face masks were attached to the mannequin heads, and the viral loads and infective virus that passed through the masks were measured by use of a plaque assay and quantitative real-time reverse transcription PCR (qRT-PCR), respectively. The nebulizer was charged with virus suspension (5 × 10 5 PFU, 1 × 10 8 PFU, 1 × 10 5 PFU, and 1 × 10 4 PFU ) to generate droplets/aerosols and exhaled continuously to simulate a mild cough at a flow speed of 2 m/s for 20 min. Mask protective efficiency against SARS-CoV-2 droplets/aerosols. IMPORTANCE Airborne simulation experiments showed that cotton masks, surgical masks, and N95 masks provide some protection from the transmission of infective SARS-CoV-2 droplets/aerosols however, medical masks (surgical masks and even N95 masks) could not completely block the transmission of virus droplets/aerosols even when sealed.ĬOVID-19 N95 masks SARS-CoV-2 aerosols droplets face masks. Our data will help medical workers understand the proper use and performance of masks and determine whether they need additional equipment to protect themselves from infected patients. Importantly, medical masks (surgical masks and even N95 masks) were not able to completely block the transmission of virus droplets/aerosols even when completely sealed. We found that cotton masks, surgical masks, and N95 masks all have a protective effect with respect to the transmission of infective droplets/aerosols of SARS-CoV-2 and that the protective efficiency was higher when masks were worn by a virus spreader.
KEYLIGHT 1.2 INSIDE MASK SIMULATOR
Here, we developed an airborne transmission simulator of infectious SARS-CoV-2-containing droplets/aerosols produced by human respiration and coughs and assessed the transmissibility of the infectious droplets/aerosols and the ability of various types of face masks to block the transmission. Guidelines from the CDC and the WHO recommend the wearing of face masks to prevent the spread of coronavirus (CoV) disease 2019 (COVID-19) however, the protective efficiency of such masks against airborne transmission of infectious severe acute respiratory syndrome CoV-2 (SARS-CoV-2) droplets/aerosols is unknown.
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