In this Monday, Dec. 7, 2020, file photo, critical care nurses and respiratory therapists flip a patient with COVID-19 upright at North Memorial Health Hospital in Robbinsdale, Minn. Virtually every state is reporting surges in cases and deaths. (File photo: AP)

NEW YORK, Dec. 8 (Xinhua) -- The number of COVID-19 cases in the United States surpassed 15 million on Tuesday, according to the Center for Systems Science and Engineering at Johns Hopkins University.