By the time New York City confirmed its first case of coronavirus on March 1, some 10,000 infections were already invisibly spreading through the city, new research estimates https://nyti.ms/2VysPYx 

On March 1, there were only about two dozen confirmed coronavirus cases across Boston, Chicago, New York, San Francisco and Seattle. Political leaders were questioning how severe and how disruptive the outbreak would become. https://nyti.ms/2VysPYx 

But while testing had confirmed few cases, the virus was scattering locally through multiple cities and seeding blooms of infection across the country, a research team from Northeastern University found https://nyti.ms/2VysPYx 

Researchers’ estimates indicate that even on March 1 there were about 28,0000 infections in five cities https://nyti.ms/2VysPYx 

Modeling the spread of a disease is inherently inexact. It uses estimates of how often people come in contact and transmit the virus as they travel, work and socialize. But
other researchers said the findings were broadly in line with their own thinking. https://nyti.ms/2VysPYx