"conclude that the infectivity of some asymptomatic SARS-CoV-2 carriers might be weak. "
A single asymptomatic person test? How long had they had it????
Newer research shows that about 24 hours before the onset of symptoms they can spread it with ease in a room full of people in choir practice by simply singing, newer more authoritative data.
"No severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections was detected in 455 contacts by nucleic acid test."
"All patients also wore masks except for eating or drinking and were admitted to infectious department for medical isolation"
"In total, 196 family members were enrolled. The situation on wearing masks was the same as that in patients. "
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