Report from WHO disease modeling team estimates two-thirds of global coronavirus cases have gone undetected
A new report from a WHO infectious disease modeling team based at Imperial College London is estimating about two-thirds of Covid-19 cases worldwide have gone undetected. The analysis suggests the global spread of the novel coronavirus is significantly greater than the current volume of confirmed cases. “We are starting to see more cases reported from countries and regions outside mainland China with no known travel history or link to Wuhan City,” explains Natsuko Imai, one of the authors on the new report. “Our analysis, which extends and confirms previously released analysis by other groups using flight volumes from Wuhan City and the reported number of COVID-19 cases, demonstrates the importance of surveillance and case detection if countries are to successfully contain the epidemic.”
As of February 23, 2020, there are over 78,000 confirmed cases of Covid-19, the vast majority of which are concentrated in China. Prior studies have suggested most cases present with mild symptoms. Only a small minority of confirmed cases seem to progress into serious pneumonia-like disease, leading some researchers to suggest the virus may have spread wider than current numbers indicate. This new report set out to explore how accurate current country-based surveillance of the disease may be, in relation to the average volume of travelers flying out of the epidemic epicenter in Wuhan, China.