The United States on Friday declared a public health emergency and announced significant entry restrictions because of a new virus that hit China and has spread to other nations.

Health and Human Services Secretary Alex Azar, who is co-ordinating the federal response, announced that U.S. President Donald Trump has signed an order that will temporarily bar entry to the U.S. of foreign nationals, other than immediate family of U.S. citizens and permanent residents, who have travelled in China within the last 14 days. The new restrictions take effect at 5 p.m. ET on Sunday.

"It is likely that we will continue to see more cases in the United States in the coming days and weeks, including some limited person-to-person transmissions," Azar said. "The American public can be assured the full weight of the U.S. government is working to safeguard the health and safety of the American people."

Americans returning from China will be allowed into the country, but will face screening at select ports of entry and required to undertake 14 days of self-screening to ensure they don't pose a health risk. Those returning from Hubei province, the centre of the outbreak, will be subject to up to 14 days of mandatory quarantine.

Beginning Sunday, the U.S. will also begin funnelling all flights to the U.S. from China to seven major airports where passengers can be screened for illness.

A public health emergency in the U.S. allows the government to tap additional resources to send to states, such as emergency funding and if necessary drugs or equipment from the national stockpile, and to suspend certain legal requirements.

Robert Redfield, director of the Centers for Disease Control and Prevention, said that while the risk in the U.S. is low, "I want to emphasize that this is a significant global situation and it continues to evolve."

The U.S. confirmed a seventh case of the virus on Friday. All were travellers except for a Chicago man who caught it from his wife, who had been in China.

The total number of deaths from the coronavirus in China had reached 259 by the end of Friday, state broadcaster CCTV said, citing numbers from the country's National Health Commission. It said 45 of the new deaths were in Hubei province, and one in the municipality of Chongqing.

It also said there were 2,102 new confirmed infections in China, bringing the total accumulated number to 11,791.

'Very stressful and unhappy'

At least 196 Canadians have asked Ottawa for help getting out. But China is preventing dual citizens, a status not recognized in China, from leaving.

Wayne Tremblay and his wife, who is a dual citizen, say they are stuck just outside Wuhan. They travelled to be with her relatives for Lunar New Year. But now he and his wife have agreed he should fly home on the Canadian chartered flight.

"If I can go back, I need to go back and get to work and provide for our family because the other possibility is being away from work and without income for a month, or a month and a half. Nobody really knows," he told CBC's Heather Hiscox.

"It's a very stressful and unhappy decision."

A medical worker in a protective suit checks the body temperature of a driver at a checkpoint outside the city of Yueyang, Hunan Province, near the border to Hubei Province that is on lockdown after the outbreak of a coronavirus. (Thomas Peter/Reuters)

Prime Minister Justin Trudeau told reporters Friday that Canada is "deliberately engaging" the Chinese authorities around repatriating the Canadians who are concerned for their safety in China.

François-Philippe Champagne, Canada's minister of foreign affairs, discussed the outbreak with his Chinese counterpart Wang Yi.

In a statement, Champagne said Wang reacted "positively" to his request for helping the "Canadian citizens who want to depart the region."

Low risk in Canada

Case numbers are increasing in China, but there's been no widespread transmission outside that country.

The Public Health Agency of Canada, which is working alongside provinces and territories to monitor the novel coronavirus, says the risk to Canadians is low.

Dr. Michael Gardam, an infectious disease specialist in Toronto, explains what's happening with the virus and what Canadians should be aware of.

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Global Affairs Canada has authorized a limited departure of staff and dependents. All children of GAC staff who are school aged and younger are permitted to leave along with those who have medical conditions, mental health concerns or other vulnerabilities.

Other staff have been given approval to undertake flexible work arrangements, including working remotely, GAC said.

In Canada, officials at a Toronto hospital said Friday that a man who had been diagnosed with coronavirus was released from hospital.

"Over the course of the week, his status continued to improve to the point where he no longer required in-patient care," Sunnybrook Health Sciences Centre said in a statement.

The virus in China has been centred in Wuhan, in Hubei province. Wuhan's mayor, Zhou Xianwang, said Friday that health-care workers have an inadequate supply of masks and other medical supplies.

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Infectious disease specialist says risk to Canadians is low 0:46

Germany's research minister said on Friday she expected a vaccine for coronavirus to be developed within months.

"If we want to contain this illness then it is good if we have a vaccine in a relatively short time, and we assume this will be in a few months," said Research Minister Anja Karliczek.

The announcement came after biopharmaceutical company CureVac AG and the Coalition for Epidemic Preparedness Innovations (CEPI) said they were working together to develop a vaccine against the virus, first detected in China in December.

Read more about what's happening with coronavirus