According to the report of national public radio (NPR) on February 6 local time, the research team of Columbia University has established a digital model to show people the spread of the virus in a more comprehensive and intuitive way. The latest research conclusion shows that on any day, the actual active cases in the United States, that is, people newly infected or still infectious, may be 10 times the number of officially reported cases on that day. Throughout the pandemic, the number of people infected in the United States was far five times higher than actually reported. However, with the epidemic becoming more and more serious, the daily detection rate in the United States has increased. The research model found that only one tenth of the cases were identified and reported at the beginning of the epidemic. This phenomenon will not improve until early May 2020, and this proportion will rise to one sixth, and one fifth by September.

Shaman estimated that in the past three months, the average number of officially counted infections was only one quarter. In other words, if people want to know accurate data, they need to multiply the official daily reports by four to get the actual number of new cases per day.