So far the fatalities are quite low. Why are health experts so worried about it?
Experts say the international community is concerned about the virus because so little is known about it and it appears to be spreading quickly.
It is similar to SARS, which infected 8,000 people and killed nearly 800 in an outbreak in Asia in 2003, in that it is a type of coronavirus which infects humans' lungs.
Another reason for concern is that nobody has any immunity to the virus because they've never encountered it before. This means it may be able to cause more damage than viruses we come across often, like the flu or common cold.
Speaking at a briefing in January, Oxford University professor, Dr Peter Horby, said: 'Novel viruses can spread much faster through the population than viruses which circulate all the time because we have no immunity to them.
'Most seasonal flu viruses have a case fatality rate of less than one in 1,000 people. Here we're talking about a virus where we don't understand fully the severity spectrum but it's possible the case fatality rate could be as high as two per cent.'
If the death rate is truly two per cent, that means two out of every 100 patients who get it will die.
'My feeling is it's lower,' Dr Horby added. 'We're probably missing this iceberg of milder cases. But that's the current circumstance we're in.
'Two per cent case fatality rate is comparable to the Spanish Flu pandemic in 1918 so it is a significant concern globally.'
How does the virus spread?
The illness can spread between people just through coughs and sneezes, making it an extremely contagious infection. And it may also spread even before someone has symptoms.
It is believed to travel in the saliva and even through water in the eyes, therefore close contact, kissing, and sharing cutlery or utensils are all risky.
Originally, people were thought to be catching it from a live animal market in Wuhan city. But cases soon began to emerge in people who had never been there, which forced medics to realise it was spreading from person to person.
There is now evidence that it can spread third hand – to someone from a person who caught it from another person.
What does the virus do to you? What are the symptoms?
Once someone has caught the COVID-19 virus it may take between two and 14 days, or even longer, for them to show any symptoms – but they may still be contagious during this time.
If and when they do become ill, typical signs include a runny nose, a cough, sore throat and a fever (high temperature). The vast majority of patients – at least 97 per cent, based on available data – will recover from these without any issues or medical help.
In a small group of patients, who seem mainly to be the elderly or those with long-term illnesses, it can lead to pneumonia. Pneumonia is an infection in which the insides of the lungs swell up and fill with fluid. It makes it increasingly difficult to breathe and, if left untreated, can be fatal and suffocate people.
What have genetic tests revealed about the virus?
Scientists in China have recorded the genetic sequences of around 19 strains of the virus and released them to experts working around the world.
This allows others to study them, develop tests and potentially look into treating the illness they cause.
Examinations have revealed the coronavirus did not change much – changing is known as mutating – much during the early stages of its spread.
However, the director-general of China's Center for Disease Control and Prevention, Gao Fu, said the virus was mutating and adapting as it spread through people.
This means efforts to study the virus and to potentially control it may be made extra difficult because the virus might look different every time scientists analyse it.
More study may be able to reveal whether the virus first infected a small number of people then change and spread from them, or whether there were various versions of the virus coming from animals which have developed separately.
How dangerous is the virus?
The virus has a death rate of around two per cent. This is a similar death rate to the Spanish Flu outbreak which, in 1918, went on to kill around 50million people.
However, experts say the true number of patients is likely considerably higher and therefore the death rate considerably lower. Imperial College London researchers estimate that there were 4,000 (up to 9,700) cases in Wuhan city alone up to January 18 – officially there were only 444 there to that date. If cases are in fact 100 times more common than the official figures, the virus may be far less dangerous than currently believed, but also far more widespread.
Experts say it is likely only the most seriously ill patients are seeking help and are therefore recorded – the vast majority will have only mild, cold-like symptoms. For those whose conditions do become more severe, there is a risk of developing pneumonia which can destroy the lungs and kill you.
Can the virus be cured?
The COVID-19 virus cannot currently be cured and it is proving difficult to contain.
Antibiotics do not work against viruses, so they are out of the question. Antiviral drugs can work, but the process of understanding a virus then developing and producing drugs to treat it would take years and huge amounts of money.
No vaccine exists for the coronavirus yet and it's not likely one will be developed in time to be of any use in this outbreak, for similar reasons to the above.
The National Institutes of Health in the US, and Baylor University in Waco, Texas, say they are working on a vaccine based on what they know about coronaviruses in general, using information from the SARS outbreak. But this may take a year or more to develop, according to Pharmaceutical Technology.
Currently, governments and health authorities are working to contain the virus and to care for patients who are sick and stop them infecting other people.
People who catch the illness are being quarantined in hospitals, where their symptoms can be treated and they will be away from the uninfected public.
And airports around the world are putting in place screening measures such as having doctors on-site, taking people's temperatures to check for fevers and using thermal screening to spot those who might be ill (infection causes a raised temperature).
However, it can take weeks for symptoms to appear, so there is only a small likelihood that patients will be spotted up in an airport.
Is this outbreak an epidemic or a pandemic?
The outbreak is an epidemic, which is when a disease takes hold of one community such as a country or region.
Although it has spread to dozens of countries, the outbreak is not yet classed as a pandemic, which is defined by the World Health Organization as the 'worldwide spread of a new disease'.
The head of WHO's global infectious hazard preparedness, Dr Sylvie Briand, said: 'Currently we are not in a pandemic. We are at the phase where it is an epidemic with multiple foci, and we try to extinguish the transmission in each of these foci,' the Guardian reported.
She said that most cases outside of Hubei had been 'spillover' from the epicentre, so the disease wasn't actually spreading actively around the world.