Researchers of the United States believe that the coronavirus may have been spreading in the area of Everett , Washington for up to six weeks .
On February 29 , researchers announced the the coronavirus strain in the Everett , Washington high school student 's case may be related to the coronavirus strain in the first confirmed US case from January 19 , suggesting that the virus may have been spreading in the area for up to six weeks .
2020 coronavirus pandemic in the United States