The U.S. Centers for Disease Control and Prevention is warning Americans to prepare for an outbreak of the coronavirus that’s rocked China and hammered the global economy — saying it’s not a question of “if” but “when” the virus will come to the United States. The warning came as new coronavirus cases spread far beyond China’s Hubei province, the epicenter of the outbreak, where more than 50 million people remain on lockdown.

Overnight, more deaths were reported in China, Italy, Japan and in South Korea, where a U.S. soldier has been quarantined after contracting coronavirus. In Iran, where the public health system has been decimated by U.S.-led sanctions, a lawmaker says 50 people have died of coronavirus infection in the city of Qom alone. Elsewhere, Algeria has reported its first case, and Brazil has reported its possible first patient.

In the U.S., San Francisco Mayor London Breed declared a state of emergency Tuesday, even though there have been no reported cases in the Bay Area. Dr. Nancy Messonnier, director of the CDC’s Center for Immunization and Respiratory Diseases, warned Americans to prepare for serious disruptions to daily life.

Dr. Nancy Messonnier: “Some community-level interventions that may be most effective in reducing the spread of a new virus, like school closures, are also the most likely to be associated with unwanted consequences and further disruptions. Secondary consequences of some of these measures might include missed work and loss of income. I understand this whole situation may seem overwhelming and that disruption to everyday life may be severe, but these are things that people need to start thinking about now.”