NEW YORK (CBSNewYork) – The coronavirus outbreak continues to grow. In China, the virus has killed at least 259 people and infected nearly 12,000.

There were seven confirmed cases in the United States on Friday, reports CBS2’s Jessica Layton.

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An eighth U.S. case was confirmed Saturday in Massachusetts. The man lives in Boston and recently returned from Wuhan, China.

Under the public health emergency, anyone who’s not a U.S. citizen will not be allowed into the country if they could potentially pass on the virus here.

“Foreign nationals other than the immediate family of U.S. citizens and permanent citizens who have traveled in China in the last 14 days will be denied entry into the United States during this time,” said Secretary of Health and Human Services Alex Azar.

The extraordinary step was announced a day after the first person-to-person transmission in the U.S. and a San Francisco Bay Area man became the seventh American case. He was recently in Wuhan, the epicenter of the outbreak.

“This case was careful to self-isolate for the entire time since returning from China,” said Public Health Director Sarah Cody.

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“This is a significant global situation and it continues to evolve,” said Robert Redfield, director of the Centers for Disease Control and Prevention. But I also want to emphasize the risk at this time to the American public is low.”

They want to keep it that way. Starting Sunday, any U.S. citizen coming home whose been in Hubei province in the last two weeks is subject to 14 days of mandatory quarantine. Already 195 Americans who were evacuated from Wuhan are being housed at a military base in California.

“No one’s coughing,” said Jerrod Evans, one of the people in the first federal quarantine in 50 years. He recorded video from where they are staying. “We’re all wearing masks, even when we’re outside in this group. I’m personally wearing gloves.”

Airlines are taking major steps as well: Delta and American are temporarily stopping all flights between the U.S. and China. United is suspending flights to three major Chinese cities but will continue flying to Hong Kong.

Friday stocks tumbled on fears the spread of the virus could hurt the global economy with all three major indexes down.

The orders under the new public health emergency take effect Sunday at 5 p.m. Health officials are also asking Americans coming home who’ve been anywhere in China at all to monitor themselves for two weeks.

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Companies in China taking precautions as well. Apple announced Saturday morning that it will shut down all its stores in mainland China, through Feb. 9 out of an “abundance of caution.”