Declaring a PHEIC could also galvanize global attention to the need to address the outbreak, which has sickened hundreds and killed at least 17 people in China, and led to cases in countries including Thailand, Japan, South Korea, and, as of Tuesday, the United States.
Two cases have been confirmed so far in Vietnam- a Chinese man living in Ho Chi Minh City, who was infected by his father who travelled to Vietnam on January 13 from the Chinese city of Wuhan.
Another patient is being tested to rule out coronavirus at Belfast's Royal Victoria Hospital, it is understood.
Samples are being sent in category A transport to a laboratory in London for urgent testing.
The head of infection medicine at the University of Edinburgh, Professor Jurgen Haas, confirmed that three of the cases are in Edinburgh whilst the fourth is believed to be in Glasgow.
World Health Organization defines a global emergency as an "extraordinary event" that constitutes a risk to other countries and requires a coordinated worldwide response.
"In our experience during SARS, we scanned millions of people and didn't pick up a single case", she said.
Week-long celebrations to welcome the Year of the Rat began on Friday, raising fears that the infection rate could accelerate as hundreds of millions of people travel to see family at home and overseas.
Any suspected cases have to be isolated and staff dealing with them must wear protective clothes including gloves, masks and goggles.
Those most affected are older people and those with underlying health conditions.
A 66-year-old man surnamed Luo reported a "mainly dry cough" but no fever on December 22 before suffering from shortness of breath more than a week later.
The Scottish Government has confirmed five people are being examined after presenting with symptoms of the illness.
No health concerns have been raised.
"We are co-orientating with Health Protection Scotland a daily Incident Management Team to continue to monitor the situation as it develops, including on the number of any potential cases going forward".
Tollways on roads out of the city were also shut down.
Also on Thursday, ahead of the World Health Organization decision, the U.S. Centers for Disease Control and Prevention raised its travel notice for China to the highest level of 3 for Wuhan, advising against nonessential travel. The two cities put together have a population of over 17 million people.
The World Health Organisation (WHO) has said it is "too early" to declare an global public health emergency over the coronavirus outbreak as six people are tested for the illness in the UK.
"Obviously, we take very seriously this issue of the coronavirus", Prime Minister Justin Trudeau said Thursday.
Those travel restrictions have been extended to the nearby cities of Huanggang and Ezhou, both in China's Hubei province.
Giving details on infections in China, Chinese state television said 634 cases had been confirmed.
During a visit to Wuhan, Vice Premier Sun Chunlan said authorities needed to be open about the virus and efforts to contain it, the official Xinhua news agency said.