Patients with undiagnosed flu symptoms who actually had COVID-19 last winter in various parts of the world were among the thousands of undetected cases of the disease earlier this year, according to a new article published in the journal ‘EClinicalMedicine’.
In this research, epidemiological researchers from the University of Texas at Austin (USA) have estimated that COVID-19 was much more widespread in Wuhan (China) and Seattle weeks before the confinement measures in each city.
When the Chinese government closed Wuhan on January 22, there were 422 known cases. But, by extrapolating the data from throat swabs across the city using a new epidemiological model, these researchers found that there may have been more than 12,000 undetected symptomatic cases of COVID-19.
Specifically, they note that in the United States about one-third of the estimated undiagnosed cases were in children. The researchers also concluded that the first case of COVID-19 in Seattle may have arrived as early as Christmas or New Year’s Day.
The research team worked to extrapolate the scope of the COVID-19 epidemic in Wuhan and Seattle based on reexamined throat swabs taken from patients suffering from influenza-like illness during January in Wuhan and during late February and early March in Seattle. When the samples were tested later in each city, most turned out to be flu, but some tested positive for SARS-CoV-2, the virus that causes COVID-19.