The WHO initially indicated on January 14 before the pandemic in the US that there was no clear evidence of human-to-human transmission of the coronavirus .
An American citizen , after traveling from Wuhan , China , to his home in Washington state , became the first U.S. case of the new virus on January 20 . `` First Case of 2019 Novel Coronavirus in the United States '' , The New England Journal of Medicine , March 5 , 2020 The WHO initially indicated on January 14 that there was `` no clear evidence of human-to-human transmission '' but on January 22 that further investigation suggested `` human-to-human transmission is taking place '' .
2020 coronavirus pandemic in the United States