China Coronavirus May Have Infected at Least 4,000 People, Experts Believe

At least 4,000 people may have been infected by a mysterious virus thought to have originated in China, experts believe.

Since health officials became aware of the virus in the central Chinese city of Wuhan in December last year, a total of 17 people have died and 555 cases have been confirmed by Chinese health officials, according to a map updated by Johns Hopkins University.

However, experts in forecasting the spread of infectious diseases, known as modeling, at Imperial College London in the U.K. believe a total of 4,000 cases of the virus could have occurred in Wuhan by January 18. The virus was initially linked to workers at a seafood market in the city.

"It is likely that the outbreak of a novel coronavirus in Wuhan has caused substantially more cases of moderate or severe respiratory illness than have currently been detected and reported," the team said.

But they explained that a recent rapid spike in officially reported cases in China indicates that detection and reporting has been "substantially enhanced in recent days." As understanding of the disease grows, "it is to be hoped that the differences between our estimates and official case numbers will lessen further," they said.

The team estimates the size of the outbreak in Wuhan has more than doubled since its first forecast a few days ago. "This is a result of the number of cases detected outside mainland China having increased from 3 to 7," the researchers said.

But the team cautioned: "Our estimates should not be interpreted as implying the outbreak has doubled in size in the period 12th January to 18th January—delays in confirming and reporting exported cases and incomplete information about dates of symptom onset together with the still very small numbers of exported cases mean we are unable to estimate the epidemic growth rate at the current time."

The researchers arrived at the figure by looking at the data including the catchment population of Wuhan International Airport, which is 19 million people, as well as the total volume of international travel from the city in the past two months, and the potential effects of screenings of people leaving the city. The team also considered the average 10-day gap between the time a person is infected and the disease is detected.

The estimate comes after the first case of the bug—which is a member of the large coronaviruses family that can cause conditions as mild as the common cold to more severe infections like Severe Acute Respiratory Syndrome (SARS)—was identified in the U.S.

At the start of January, the CDC put in place a number of precautions against the potential spread of the bug, dubbed 2019-nCoV. That includes health officials being alert to patients who have been to Wuhan and returned with respiratory symptoms. Symptoms of 2019-nCoV include a fever, dry cough, shortness of breath and trouble breathing.

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A Chinese police officer wears a protective mask as he stands guard at Beijing Station before the annual Spring Festival on January 22, 2020 in Beijing, China. The number of cases of a deadly new coronavirus rose to over 400 in mainland China Wednesday as health officials stepped up efforts to contain the spread of the pneumonia-like disease which medicals experts confirmed can be passed from human to human. Kevin Frayer/Getty Images)