One of the hazards of scientifically naive people attempting to read scientific articles is the failure to understand what they read. No serious researcher ever relies on the introductory abstract.
These are written to satisfy editors, not to convey accurate information. Turn to the Method section and the Results section and peruse the statistics. The Leung et al article clearly documents that there was no statistically significant difference between mask and no mask conditions for hypothetical transmission of Covid 19.
From Results:
“We detected coronavirus in respiratory droplets and aerosols in 3 of 10 (30%) and 4 of 10 (40%) of the samples collected without face masks, respectively, but did not detect any virus in respiratory droplets or aerosols collected from participants wearing face masks, this difference was significant in aerosols and showed a trend toward reduced detection in respiratory droplets (Table 1b).”
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