As the weekend comes to an end, the burning question remains whether 2019_nCoV is transmitted by infected persons before clinical symptoms are obvious. Yesterday, I summarized the description of a Chinese family of seven that visited Wuhan and became infected without visiting the market, that is still being considered the “source” of the outbreak. Indeed, there were 2 family members without symptoms, and one of them (patient #5) not only had similar symptoms as family members on pulmonary CT, but also tested positive for the spike gene in the respiratory tract sample (thank you readers for pointing this out to me).
Today, newspapers reported that the observed incubation periods of the virus had ranged from 1 to 14 days and that the virus could be transmitted in this period. Apparently, this was communicated by the Chinese authorities, but a source of this data was not reported. Unless this is the source, see. I haven’t seen data, and it may still be based on rare events.
And the R_0 estimates keep coming in; all within the range from 2 to 5 (what I saw). But there is also warning against over-interpretation of these early-derived estimates. The population will respond to what is happening, trying to avoid infection, and that in itself may already reduce the effective R_0, as happened with SARS. Yet, in Wuhan the situation seems compatible with R_0 values as reported, a short generation time and transmission before symptoms occur.
Compared to Friday night, little – if any – news to think this will pass unnoticed.