The doctor who treated America’s first coronavirus patient believes it has been secretly spreading across the US for “several weeks,” according to a report.

“I do think that this virus has been circulating now for several weeks in the US,” Dr. Amy Compton-Phillips told CNBC.

“Until now, it’s been circulating unchecked,” she said.

Compton-Phillips said medical workers all knew “this is coming,” saying, “It’s not if, it’s when. And we better get ready now.”

Her fears came to fruition when she ended up treating a 35-year-old Washington man who had landed at Seattle-Tacoma International Airport on Jan. 15 from the outbreak’s epicenter in Wuhan, China.

She said Providence St. Joseph Health, where she is the chief clinical officer, took an “overkill” approach and presumed it was COVID-19 “until proven otherwise.”

The unidentified patient was put in an isolation room in a “special gurney with plastic around it, so he wouldn’t contaminate anything,” she told CNBC.

His symptoms soon went from being like a common cold to shortness of breath and a cough, with his X-ray confirming viral pneumonia.

He needed supplemental oxygen and had to be put on an experimental antiviral treatment, she said.

He eventually recovered and was discharged from the hospital.