As many as 4,000 people in the city at the epicentre of an outbreak of a mystery new coronavirus could be infected with the disease, experts have warned.
So far, Chinese authorities say roughly 500 people have fallen ill and nine people have died from the disease, which was first identified in China at the end of last year and has now spread to five other countries, including the United States.
Experts say it is also "possible" that a case could reach the UK.
But disease modelling experts from Imperial College, London say the true figure in the city of Wuhan alone - the source of the outbreak - could be 4,000 and as high as 9,700 in the worst case scenario.
At the weekend the researchers released figures estimating that around 1,700 people in the city were infected - at the time Chinese officials said there were just 40 cases of the disease.
Neil Ferguson, professor of mathematical biology at Imperial College, told a press briefing in London that over the coming weeks the number of cases would increase rapidly.
He added: “We’ve updated our estimates of the number of cases to a central estimate of about 4,000 in Wuhan. It will be much more complicated to estimate for the whole of China."
He said this was nearly double the previous estimate.
“It’s not that the epidemic has doubled in size in the last five days but that more information has been gathered and more cases have been exported [to other countries],” he said.
Prof Ferguson added that it is “possible” that the virus could reach the UK and Europe, particularly if the outbreak lasts a long time.
The new virus is from the same family as the severe acute respiratory syndrome virus that swept through the world in 2002 to 2003. That too originated in China and eventually infected around 8,000 people, killing 800.
Earlier today transport secretary Grant Shapps said that travellers arriving at Heathrow airport directly from Wuhan would be put in a separate area.
“There have been some announcements this morning about flights that come direct from the affected region to Heathrow with some additional measures there,” he told Sky News.
“At the moment Public Health England have moved this from 'very low' to 'low' but obviously we want to stay ahead of the issue so we are keeping a very close eye on it.
“Initially this is to ensure that when flights come in directly into Heathrow there is a separate area for people to arrive in." The Foreign Office has updated its advice for Britons travelling to China, warning the virus had spread to other areas outside the Hubei province.
The Foreign Office has updated its advice for Britons travelling to China, warning the virus had spread to other areas outside the Hubei province.
The World Health Organisation (WHO) is expected to meet later today to decide if the outbreak should be categorised as a public health emergency.
The agency has only used the rare label a handful of times, including during the H1N1 – or swine flu – pandemic of 2009 and the current Ebola outbreak that authorities are struggling to control in the Democratic Republic of Congo.
“I suspect we’re edging towards a decision being made that it is a public health emergency of international concern, just based on the new data emerging today,” Professor Ferguson, told The Telegraph on Tuesday.
Protect yourself and your family by learning more about Global Health Security