"Japan’s population is about 38% of the U.S., but even adjusting for population, the Japanese death rate is a mere 2% of America’s.

This comes despite Japan having no lockdown, still-active subways, and many businesses that have remained open—reportedly including karaoke bars, although Japanese citizens and industries are practicing social distancing where they can. Nor have the Japanese broadly embraced contact tracing, a practice by which health authorities identify someone who has been infected and then attempt to identify everyone that person might have interacted with—and potentially infected. So how does Japan do it? “One reason is that nearly everyone there is wearing a mask,” said De Kai"

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"Among the findings of their research paper, which the team plans to submit to a major journal: If 80% of a closed population were to don a mask, COVID-19 infection rates would statistically drop to approximately one twelfth the number of infections—compared to a live-virus population in which no one wore masks."