New study with millions of people included.

The detection rate of asymptomatic positive cases was very low, and there was no evidence of transmission from asymptomatic positive persons to traced close contacts. There were no asymptomatic positive cases in 96.4% of the residential communities.

Existing laboratory virus culture and genetic studies9,10 showed that the virulence of SARS-CoV-2 virus may be weakening over time, and the newly infected persons were more likely to be asymptomatic and with a lower viral load than earlier infected cases.

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Kind of flies in the face of other studies. But it is the largest sample ever and is peer reviewed. On the other hand it comes from China.

"Peer review information Nature Communications thanks Junxiong Vincent Pang and the other, anonymous reviewer(s) for their contribution to the peer review of this work. Peer review reports are available."