Undetected cases, many not severely symptomatic, were largely responsible for the rapid spread of the COVID-19 outbreak in China, according to new research at Columbia University Mailman School of Public Health. The findings based on a computer model of the outbreak are published online in medRxiv.
“The explosion of COVID-19 cases in China was largely driven by individuals with mild, limited, or no symptoms who went undetected,” says co-author Dr. Jeffrey Shaman, professor of environmental health sciences. “These undetected infected individuals are numerous and contagious. These stealth transmissions will continue to present a major challenge to the containment of this outbreak going forward.”
The researchers used a computer model that draws on observations of reported infection and spread within China in conjunction with mobility data from January 10-23 and January 24-Feb. 8. They caution that major changes to care-seeking or rapid developments regarding travel restrictions and control measures, may make predictions difficult.
“Heightened awareness of the outbreak, increased use of personal protective measures, and travel restriction have helped reduce the overall force of infection; however, it is unclear whether this will be sufficient to fully stem the virus spread,” says Dr. Shaman. “If the novel coronavirus follows the pattern of 2009 H1N1, it will become a fifth endemic coronavirus within the human population.”Friday Letter Submission, Publish on March 06