New research indicates that the coronavirus began to circulate in the New York area by mid-February, weeks before the first confirmed case, and that it was brought to the region mainly by travelers from Europe, not Asia…

The research revealed a previously hidden spread of the virus that might have been detected if aggressive testing programs had been put in place. On Jan. 31, President Trump barred foreign nationals from entering the country if they had been in China — the site of the virus’s first known outbreak — during the previous two weeks.