- Japan’s low death rate - 2% of the US - comes despite a lack of a lockdown and a limited programme of contact tracing. BUT virtually everyone there wears masks. - “The masksim simulator...allowed [researchers] to create scenarios of populations like those in Japan (that generally wear masks) and others (that generally don’t), and to compare what happens to infection rates over time. - “This is the goal,” De Kai maintained. “For 80 or 90% of the population to be wearing masks.” Anything less, he added, doesn’t work as well. “If you get down to 30 or 40%, you get almost no [beneficial] effect at all.”