Top U.S. public health officials said Tuesday that Americans should prepare for the spread of the coronavirus in communities across the country.

“It’s not so much a question of if this will happen any more, but rather more a question of exactly when this will happen and how many people in this country will have severe illness,” Dr. Nancy Messonnier, the head of Centers for Disease Control and Prevention’s National Center for Immunization and Respiratory Diseases, said during a media briefing Tuesday.

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