Wednesday, 22 January 2020

Coronavirus may have spread to Australia as man tests positive


Chinese Mystery Disease Update No 4: Hundreds of millions of Chinese are on the move this week as human-to-human transmission confirmed: Will spread more quickly and widely: No of cases in the 1000s



Photo David Paulk
  • Coronavirus Is Spreading Quickly Across China as Confirmed Cases Triple. 
  • Pneumonia-like illness is transmittable between humans, reaching major metropolitan. areas in China. 
  •  The infection spreads to Beijing and Shanghai. 
  • China confirms new SARS-like virus HAS spread between humans as 14 medics catch the killer infection after treating patients. 
  • No need to panic” the virus was not spreading significantly within China as (hundreds of millions of Chinese are on the move for New Year holiday). 
  •  Medics in hazmat suits scanning plane passengers for China's mysterious Wuhan virus is stoking fears of a global epidemic
20 January, 2020



It is the biggest holiday in the world as hundreds of millions of Chinese are on the move this week to celebrate the Chinese New Year on Sunday, a tiny per cent of these will be unknowingly carrying the mysterious coronavirus, which has just been confirmed can be passed on to humans by humans. The scenario which will follow this is horrific.

The head of a Chinese government expert team said Monday that human-to-human transmission has been confirmed in an outbreak of a new coronavirus, a development that raises the possibility that it could spread more quickly and widely. Team leader Zhong Nanshan, a respiratory expert, said two people in Guangdong province in southern China caught the virus from family members, state media said. Some medical workers have also tested positive for the virus, the English-language China Daily newspaper reported. The late-night announcement capped a day in which authorities announced a sharp uptick in the number of confirmed cases to more than 200, and China’s leader called on the government to take every possible step to combat the outbreak. Now that is the official version, below is the truth.

Published 4 days ago

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


This appears to have reached Australia

Chinese coronavirus may have spread to Australia as man tests positive



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