Two-and-a-half months after the outbreak began, the coronavirus has officially been declared a pandemic by the World Health Organisation.
There are about 125,000 confirmed and suspected cases worldwide, and over 4,500 deaths. The number of cases outside of China has risen 13-fold in the past two weeks.
But what does a pandemic mean?
The World Health Organisation defines a pandemic as "an outbreak of a new pathogen that spreads easily from person to person across the globe".
Much of the world has been watching COVID-19 spread rapidly within and between countries for several weeks - with roughly one third of cases now outside of China, where the outbreak started.
The official declaration of a pandemic means the disease has reached a tipping point where it spreads on a far wider geographic scale - sweeping through populations faster.
It comes from the Greek words pan, meaning all, and demos, meaning people, to essentially say it is growing in several countries simultaneously.
To classify as a pandemic, a disease must also be contagious. There are many globally widespread illnesses (such as cancer) that are not infectious, meaning they cannot be described this way.
Has it suddenly become far more deadly?
A pandemic does not refer to an increase in the potency or deadliness of a disease, but solely a growth in its spread.
A wider spread does increase the likelihood of fatalities, but pandemic status does not officially mean more people are suddenly dying from COVID-19, the disease caused by the coronavirus.
The timing of this declaration is also not black and white, with the threshold differing between epidemiologists.
How does an epidemic become a pandemic?
An epidemic refers to the spread of illness in a "community or region... clearly in excess of normal expectancy" - or a cluster of outbreaks in a number of countries.
Once this spread becomes increasingly global and out of control, it becomes a pandemic. The latter has to have self-sustaining links of infection.
A UK resident who catches coronavirus in China and comes home would not result in a pandemic being declared, even if they infect a close circle of people. But if they sparked a local outbreak that could not be contained - an outbreak that snowballed to many countries - a pandemic would occur.
By this stage it could have self-sustaining links of infection - so there may be swaths of emerging outbreaks with no apparent links to the epicentre, which in this case is China.
The WHO released a 2017 report which listed the four phases of a pandemic:
What's happened in the past - and what happens next?
In 2009, the H1N1 swine flu outbreak was called a pandemic but it turned out to be mild, leading to criticism after pharmaceutical companies rushed development of vaccines and drugs.
It is important to note that the coronavirus is more deadly than the swine flu, which infected between 700 million and 1.4 billion people worldwide but only had a mortality rate of 0.02%.
WHO director general, Dr Tedros Adhanom Ghebreyesus, said the health agency is not changing its advice on what countries should do.
However, he said countries must ramp up their efforts by ensuring they detect, test, treat, isolate, trace and mobilise their people.
He added that individuals must take the importance of vigorous personal hygiene seriously, while staying up-to-date with the latest official advice.