New Chinese virus infected hundreds: "I am substantially more concerned than I was a week ago," disease outbreak scientist: Actual number could be over 2,000 infected NOT 45 confirmed cases

The number of people already infected by the mystery virus emerging in China is far greater than official figures suggest, scientists have told the BBC. There have been 45 laboratory-confirmed cases of the new virus, but UK experts estimate the figure is closer to 1,700. Two people are known to have died from the virus, which appeared in Wuhan city in December. "I am substantially more concerned than I was a week ago," disease outbreak scientist, Prof Neil Ferguson, said. The work was conducted by the MRC Centre for Global Infectious Disease Analysis at Imperial College London, which advises bodies including the UK government and the World Health Organization.
Below is the summary from the disease outbreak scientist, Prof Neil Ferguson:

We estimate that a total of 1,723 cases of 2019-nCoV in Wuhan City (95% CI: 427 – 4,471) had onset of symptoms by 12th January 2020 (the last reported onset date of any case). This estimate is based on the following assumptions: Wuhan International Airport has a catchment population of 19 million individuals. There is a mean 10-day delay between infection and detection, comprising a 5-6 day incubation period and a 4-5 day delay from symptom onset to detection/hospitalisation of a case (the cases detected in Thailand and Japan were hospitalised 3 and 7 days after onset, respectively) Total volume of international travel from Wuhan over the last two months has been 3,301 passengers per day. This estimate is derived from the 3,418 foreign passengers per day in the top 20 country destinations based on 2018 IATA data, and uses 2016 IATA data held by Imperial College to correct for the travel surge at Chinese New Year present in the latter data (which has not happened yet this year) and for travel to countries outside the top 20 destination list.

Caveats

1. We assume that outbound trip durations are long enough that an infected Wuhan resident travelling internationally will develop symptoms and be detected overseas, rather than being detected after returning to Wuhan. We also do not account for the fact that international visitors to Wuhan (such as the case who was detected in Japan) might be expected to have a shorter duration of exposure and thus a lower infection risk than residents. Accounting for either factor correctly requires additional data but would increase our estimate of the total number of cases.
2. We estimate the potential number of symptomatic cases with disease severity of a level requiring hospitalisation (both the cases detected in Thailand and Japan were moderately severe). Our estimates do not include cases with mild or no symptoms.
3. The incubation period of 2019-nCov is not known and has been approximated with the estimates obtained for MERS-CoV and SARS [8,9].
4. We assume that international travel is independent of the risk of exposure to 2019n-CoV or infection status. If zoonotic exposure was biased towards wealthier people, travel frequency may be correlated with exposure. Also, some travel might be causally linked to infection status (to seek healthcare overseas) or the infection status of contacts in Wuhan (this may apply to the case detected in Japan) [10]. Accounting for either association would increase the probability of a case travelling and therefore reduce our estimates of the total number of cases.

Sensitivity analysis

We explore the sensitivity of estimates of total cases to our assumptions about: i) the duration of the detection window (exploring a lower value of 8 days); ii) the catchment population size of Wuhan airport (assuming it might be 11 million, the population of Wuhan city, rather than 19 million, the population of the entire metropolitan area); and iii) true exportations reported internationally (2, 3 and 4 cases). Table 1 summarises the baseline assumptions and alternative scenarios explored. We note that the currently reported number of cases (44) is substantially lower than the lower bound of our most conservative scenario (190 cases, Scenario 3).

Conclusions

It is likely that the Wuhan outbreak of a novel coronavirus has caused substantially more cases of moderate or severe respiratory illness than currently reported. The estimates presented here suggest surveillance should be expanded to include all hospitalised cases of pneumonia or severe respiratory disease in the Wuhan area and other well-connected Chinese cities. This analysis does not directly address transmission routes, but past experience with SARS and MERS-CoV outbreaks of similar scale suggests currently self-sustaining human-to-human transmission should not be ruled out. MRC Centre for Global Infectious Disease

The US to screen airline passengers from China for the new illness 

Three U.S. airports will screen passengers arriving from central China for a new virus that has sickened dozens, killed two and prompted worries about an international outbreak, health officials said Friday.

Centres for Disease Control and Prevention officials say they will begin taking temperatures and asking about symptoms of passengers at three U.S. airports who travelled from the outbreak city of Wuhan.

Officials estimate roughly 5,000 passengers will go through the process in the next couple of weeks at New York City’s Kennedy airport and the Los Angeles and San Francisco airports. The first direct flight was expected Friday night at Kennedy, and the next expected Saturday morning in San Francisco.

Doctors began seeing a new type of viral pneumonia — fever, cough, difficulty breathing — in people who worked at or visited a food market in the suburbs of Wuhan late last month. More than 45 cases of the newly identified coronavirus have been confirmed in Asia, most of them in Wuhan, including two deaths — at least one involving a previous medical condition. Officials have said it probably spread from animals to people but haven’t been able to rule out the possibility that it spreads from person to person.

So far, the risk to the American public is deemed low, but the CDC wants to be prepared and is taking precautions, the CDC’s Dr Martin Cetron said. AP

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