Surgical mask partition reduces the risk of non-contact transmission in a golden Syrian hamster model for Coronavirus Disease 2019 (COVID-19)
Authors: Jasper Fuk-Woo Chan
Cuiting Luo
Anna Jinxia Zhang
Siddharth Sridhar
Zhimeng Fan
Kwok-Hung Chan
Kaiming Tang
Jianli Cao
Hin Chu
Vincent Kwok-Man Poon
Kelvin Kai-Wang To
Chris Chung-Sing Chan
Jian-Piao Cai
Kwok-Yung Yuen
Can Li
Andrew Chak-Yiu Lee
Vincent Chi-Chung Cheng
Ronghui Liang
Shuofeng Yuan
Journal: Clinical Infectious Diseases (2020)
Discipline: IMMUNOLOGY
Keywords: COVID-19; SARS-CoV-2; coronavirus; mask; transmission.
Affiliations: State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China., Department of Clinical Microbiology and Infection Control, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China., Department of Microbiology, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, China.

Abstract:  Background: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is believed to be mostly transmitted by medium- to large-sized respiratory droplets, although airborne transmission may be possible in healthcare settings involving aerosol-generating procedures. Exposure to respiratory droplets can theoretically be reduced by surgical mask usage. However, there is a lack of experimental evidence supporting surgical mask usage for prevention of COVID-19. Methods: We used a well-established golden Syrian hamster SARS-CoV-2 model. We placed SARS-CoV-2-challenged index hamsters and naive hamsters into closed system units each comprising 2 different cages separated by a polyvinyl chloride air porous partition with unidirectional airflow within the isolator. The effect of a surgical mask partition placed between the cages was investigated. Besides clinical scoring, hamster specimens were tested for viral load, histopathology, and viral nucleocapsid antigen expression. Results: Noncontact transmission was found in 66.7% (10/15) of exposed naive hamsters. Surgical mask partition for challenged index or naive hamsters significantly reduced transmission to 25% (6/24, P = .018). Surgical mask partition for challenged index hamsters significantly reduced transmission to only 16.7% (2/12, P = .019) of exposed naive hamsters. Unlike the severe manifestations of challenged hamsters, infected naive hamsters had lower clinical scores, milder histopathological changes, and lower viral nucleocapsid antigen expression in respiratory tract tissues. Conclusions: SARS-CoV-2 could be transmitted by respiratory droplets or airborne droplet nuclei which could be reduced by surgical mask partition in the hamster model. This is the first in vivo experimental evidence to support the possible benefit of surgical mask in prevention of COVID-19 transmission, especially when masks were worn by infected individuals. 

Retracted: No

PubPeer comments:
 1. In figure 7D, there are two identical images for Ki-67 staining in NC group. ![file] Figure 7D presented two identical images for Ki-67 staining in NC group 2. In table 1, the author indicated 61 samples for microarray. In table 2, only 41 samples were used for qRT-PCR of USP44. However, in the Methods section, 42 fresh-frozen tissue samples of primary human glioma were depicted. Moreover, figure 2C plotted 62 samples for qRT-PCR of USP44, and figure 2D plotted the KM survival curve for 62 samples. How many samples did the author actually use for this study? ![file] Table 1 indicated 61 samples for tissue microarray ![file] Table 2 indicated 41 samples for qRT-PCR ![file] Methods depicted 42 samples of primary human glioma ![file] Figure 2C plotted 61 samples for qRT-PCR of USP44 ![file] Figure 2D plotted the KM survival curve for 62 samples 3. In figure 5B, cell cycle of flow cytometry plot for A172-USP44-KD was not matched the bar graph. For instance, G1 phase ratio in flow cytometry is 55.76%, while the ratio was obviously larger than 60% in the bar graph. ![file] Cell cycle of flow cytometry plot for A172-USP44-KD was not matched the bar graph 4. WB images for GAPDH in figure 3 and 4 was unbelievably similar, or the same two bands for U251 and A172 cell lines. ![file] WB images for GAPDH was almost the same for two different cell lines in figure 3 ![file] WB images for GAPDH was almost the same for two different cell lines in figure 4 ,