Undetected cases, many of which were likely not severely symptomatic, were largely responsible for the rapid spread of the COVID-19 outbreak in China, according to a study by Sino-American scientists. published last year.
The study, published last year, found that even patients with mild-to-no symptoms could spread the virus. In the light of the latest American “Wuhan Lab” conspiracy disinformation, it is worth re-reading.
“The researchers used multiple sources to infer the proportion of early infections that went undetected and their contribution to virus spread. The researchers combined data from Tencent, one of the world’s largest social media and technology companies, with a networked dynamic metapopulation model and Bayesian inference to analyze early spread within China.
They estimate that ∼86% of cases were undocumented before travel restrictions were put in place. Before travel restriction and personal isolation were implemented, the transmission rate of undocumented infections was a little more than half that of the known cases. However, because of their greater numbers, undocumented infections were the source for ∼80% of the documented cases. Immediately after travel restrictions were imposed, ∼65% of cases were documented. These findings help to explain the lightning-fast spread of this virus around the world.”
OR read the scientific article here (for those who are scientifically and epidemiologically-adept):
Science. 01 May 2020:
Vol. 368, Issue 6490, pp. 489-493
Mailman School of Public Health, Columbia University. 26 May 2020