The current corona virus is causing enough of an irritant with the WHO still suggesting a soft approach is adequate. So how does that stack up?
(As this is a train wreck in progress, the reports are pending peer review so are not necessarily the last word on the subject, but the studies of interest are using methodology that is similar or the same as that conducted many years ago in the SARS outbreak).
We estimate the effective reproduction number for 2019-nCoV based on the daily reported cases from China CDC. The results indicate that 2019-nCoV has a higher effective reproduction number than SARS with a comparable fatality rate.
[5]
That is not going to look good. SARS R0 was around 2.76 (Beijing) to 3.01 (Guangzhou), it changed from location to location. Current latest R0 estimate is 4.08, and the associated study undertook a sensitivity analysis to determine a confidence interval of their answer which came out with an R0 95%CI between 3.37 and 4.77, SD=0./36. This study has higher R0 values than the WHO's estimate which was running around 1.4 to 2..
The earlier study [4] also gave early estimates that were higher than the WHO estimated an R0 of 3.11, with a 95%CI of 2.39-4.13.
Mortality rates in the study are indicating higher levels of mortality in the Chinese region, well above the WHO levels, however that has it's own interesting sidebars. SARS mortality was variable across the region, with Beijing having a rate of 7.66%, and Guangzhou having a rate of 3.61%. An initial value for 2019-nCoV is suggested at 6.5%. The methodology of estimating mortality rate in the middle of an outbreak where there is an unquantified lag for incubation to detection, and therefore incubation to fatality means the figure is pretty vague. Most if not all media and health reports have used todays confirmed cases with todays attributed fatalities, which does not reflect the lag in the numbers being used. On the other hand, for this outbreak, there is a high probability of underreporting of confirmed cases to actual cases, as a significant percentage of those infected do not appear to have symptoms that result in a confirmation. A paradoxical hope is that the underlying rate of cases is indeed underreported, and as the fatalities are all identified to the virus, then the true rate is considerably lower. Some suggestion of an underlying rate that is around 10x greater would be curiously comforting.
The effectiveness of screening alone [1][2] hints that there was little liklihood of success by using the conventional screening, no wonder the PRC went into lockdown, a day late and a dollar short, but at least they tried. Sods law was this happened over Chinese New Year; sucks to be us.
A possible glimmer of light comes from the observation that if the average infectious period is reduced to <2.3 days, then the outbreak would stop. There are ways of doing that, China has commenced such action that would alter that in essence, a mass clampdown on activity, which in a round about manner achieves the same outcome. The rest of the world is still looking for a fiddle to play. Once the genie is in your neighbourhood, (and with the ineffective screening that was originally applied, that means anywhere on the planet today that had no contact with other people for the last 30 odd days) contact control is all that is left to play with to adjust the outcome, other than therapy for those with acute symptoms. The international spread of the virus still appears to be a lower rate than the mainland PRC condition, and as yet the lack of fatalities appears to be a variance from the mainland PRC experience. The lag between known contraction of the virus and a fatality is not yet reported, and it may well be that there is a considerable lag which underlies the current variance.
The reported variation in the ACE2 receptor [6] has a small study population, but it is still consistent with most external observations to date, however, non Chinese nationals have now become confirmed in Japan and other locations. The PRC Govt is taking substantial action as indicated below, yet they are unlikely to get on top of this any time soon, the lag in the cycles has to run its course. Elsewhere, the WHO and basically every other govt has responded with less than stellar timeliness and effectiveness.
Looking at R0=4, today we are around the 8th to 10 cycle of infection, (20K- 327K cases, reported is a subset of actual cases). Without check, the global population has saturation at around 17 to 18th cycle. (5.3B- 21.5B cases, current population is ~ 8B). A fatality rate of 6.5% is pretty nasty at that point...
The figures suck enough that action to break the process is probably worth the inconvenience. Strategic opportunists will always look for an advantage, but we are all in the same lifeboat, and it is taking on water.
Limit contacts, take personal Infection Control seriously, and treat symptoms.
In the west, that is going to be seen by some as an infringement on individual freedoms, so don't expect that to be effective without some change of mindset.
We are dealing with an evolving virus, one that is changing over time, any characteristic of it may change for better or worse than it is now, only time will tell.
So glad that at least we are surrounded by great leaders as this time in history has seen fit to bless us with:
.... fill in the blanks.....
Update on pneumonia of new coronavirus infections as of 24:00 on January 30
At 04:00 on January 30, 31 provinces (autonomous regions and municipalities) and the Xinjiang Production and Construction Corps reported 1982 new confirmed cases, 157 severe cases, and 43 new deaths (42 cases in Hubei Province, Heilongjiang Province). 1 case in the province), 47 new cases were cured and discharged, and 4812 new cases were suspected.
As of 2400 on January 30, the National Health and Health Commission has received a total of 9,692 confirmed cases (31 cases in Sichuan Province were subtracted from the cumulative confirmed cases) in 31 provinces (autonomous regions, municipalities) and the Xinjiang Production and Construction Corps. A total of 213 deaths and 171 cases were cured and discharged, with a total of 15,238 suspected cases.
At present, a total of 113,579 close contacts have been tracked (21 cases of reductions in Beijing). On the day, 4,201 people were released from medical observation, and a total of 102,427 people were receiving medical observation.
A total of 28 confirmed cases were reported from Hong Kong, Macao, and Taiwan: 12 from the Hong Kong Special Administrative Region, 7 from the Macao Special Administrative Region, and 9 from Taiwan.
(Information comes from the official website of the National Health Commission)
References:
[1]
Estimated effectiveness of traveller screening to prevent international spread of 2019 novel coronavirus (2019-nCoV)
Katelyn Gostic, Ana C. R. Gomez, Riley O. Mummah, Adam J. Kucharski, James O. Lloyd-Smith
medRxiv 2020.01.28.20019224; doi: https://doi.org/10.1101/2020.01.28.20019224
[2]
Risk of 2019 novel coronavirus importations throughout China prior to the Wuhan quarantine
Zhanwei Du, Ling Wang, Simon Cauchemez, Xiaoke Xu, Xianwen Wang, Benjamin J Cowling, Lauren Ancel Meyers
medRxiv 2020.01.28.20019299; doi: https://doi.org/10.1101/2020.01.28.20019299
[3} [b]
The incubation period of 2019-nCoV infections among travellers from Wuhan, China
Jantien A. Backer, Don Klinkenberg, Jacco Wallinga
medRxiv 2020.01.27.20018986; doi: https://doi.org/10.1101/2020.01.27.20018986
[4]
Novel coronavirus 2019-nCoV: early estimation of epidemiological parameters and epidemic predictions
Jonathan M Read, Jessica RE Bridgen, Derek AT Cummings, Antonia Ho, Chris P Jewell
medRxiv 2020.01.23.20018549; doi: https://doi.org/10.1101/2020.01.23.20018549
[5]
Estimating the effective reproduction number of the 2019-nCoV in China
Zhidong Cao, Qingpeng Zhang, Xin Lu, Dirk Pfeiffer, Zhongwei Jia, Hongbing Song, Daniel Dajun Zeng
medRxiv 2020.01.27.20018952; doi: https://doi.org/10.1101/2020.01.27.20018952
[6] Single-cell RNA expression profiling of ACE2, the putative receptor of Wuhan 2019-nCov
Yu Zhao, Zixian Zhao, Yujia Wang, Yueqing Zhou, Yu Ma, Wei Zuo
bioRxiv 2020.01.26.919985; doi: https://doi.org/10.1101/2020.01.26.919985