Coronavirus: Unconfirmed cases may be behind rapid spread in China, researchers say
- Study estimates that 86 per cent of infections went undiagnosed in the two weeks before Wuhan was locked down
- Those people, who probably didn’t have severe symptoms, thought to have infected 79 per cent of documented cases
The modelling research published on Monday in Science magazine – run by the American Association for the Advancement of Science – estimated that 86 per cent of infections in the mainland were not documented in the two weeks before Wuhan, the outbreak epicentre, was locked down on January 23.
While the undocumented cases of the pneumonia-like illness were about half as contagious as the documented patients – or those with severe enough symptoms to be confirmed with the virus – they were the source of infection for 79 per cent of documented ones, according to the study.
“These undocumented infections often experience mild, limited, or no symptoms and hence go unrecognised, and, depending on their contagiousness and numbers, can expose a far greater portion of the population to the virus than would otherwise occur,” the specialists from Columbia University, the University of Hong Kong, Imperial College London, Tsinghua University, and the University of California, Davis wrote in the report.
“This high proportion of undocumented infections, many of whom were likely not severely symptomatic, appears to have facilitated the rapid spread of the virus throughout China,” it added.
