San Francisco has declared a state of emergency even though there have been no confirmed cases of the 2019 novel coronavirus (COVID-19) in the city.

The announcement was made by San Francisco Mayor London Breed on Tuesday, according to The Hill.

“The global picture is changing rapidly, and we need to step-up preparedness,” Breed said. “We see the virus spreading in new parts of the world every day, and we are taking the necessary steps to protect San Franciscans from harm.”

Breed’s statement comes after the Center for Disease Control and Prevention (CDC) warned of the possibility of an outbreak in the United States.

“As more and more countries experience community spread, successful containment at our borders becomes harder and harder,” director of the Centers for Disease Control and Prevention National Center for Immunization and Respiratory Diseases, Nancy Messonnier, said in a statement on Tuesday.

“It’s not a question of if this will happen but when this will happen and how many people in this country will have severe illnesses. Disruption to everyday life might be severe.”

In order for SF to be as prepared as possible for COVID-19 (novel coronavirus), today I made an emergency declaration to strengthen SF’s response in the case of an outbreak. To be clear, there remain no known cases originating in SF–this is about preparedness.

— London Breed (@LondonBreed) February 25, 2020

American health officials said they want people to start thinking about measures to take if the virus begins to spread in the country, such as closing schools or telecommuting, The Independent reported.

“Part of preparedness is an educated population thinking about the future,” Health and Human Services Secretary Alex Azar said. “The immediate risk to the general American public remains low, but that has the potential to change quickly.”

Azar added that there is currently no evidence the COVID-19 has spread in the U.S. other than those who have been infected overseas and a few close relatives since the alarms were raised nearly two months ago.

He also credited travel controls and mandatory quarantines, adding that government scientists are now working to develop a vaccine and are trying to perfect a test that could detect the virus.

“We cannot hermetically seal off the United States to a virus and we need to be realistic about that,” Azar said.

“We’ll have more cases in the United States, and we’ve been very transparent about that,” he continued, adding that if it happens, “we’ll work to mitigate those.”

Feature Image via Noah Friedlander (CC BY-SA 4.0)