The Wuhan Coronavirus - Plotting the data

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So far in the Wuhan coronavirus epidemic, it's been difficult to get reliable information about the virus's behaviour. The Chinese government have been releasing numbers of the infected and those who have died, but many observers believe these numbers are fictitious. Unfortunately, many Western sources haven't been giving an accurate assessment of the epidemic either. There has been a lot of downplaying of the virus's threat. This may be because the establishment don't want the economy to be disrupted. There is also the possibility that China has been influencing Western institutions to play down the issue and praise China's efforts. For example, this NTDTV video report on YouTube states that the Chinese government leaned on the World Health Organisation to delay declaring the coronavirus as a pandemic:



It's always good to know something about any news source and NTDTV is no different. Their full title is New Tang Dynasty TeleVision and they are funded and associated with the Falun Gong movement. Falun Gong was a peaceful, spiritual movement founded in China in the 1990's. It grew in popularity but then fell foul of the Chinese government. Possibly a million Falun Gong members were arrested and incarcerated. It's therefore clear that a Falun Gong television station would be happy to broadcast evidence criticising the Chinese government. This doesn't necessarily mean that they will distort their evidence. Instead, it is probably the opposite; they are one of the few organisations that will broadcast accurate information about what is going on in China, and what the Chinese government is doing.

NTDTV also broadcast this video, which seems to show that Tencent, a Chinese corporation, accidentally displayed actual numbers of infected and the numbers of deaths, due to the coronavirus epidemic. The numbers weren't there for long before being removed:



The numbers of infected were stated to be 154,000. The numbers of deaths were 24,000. The date of the display was 2nd February. Are these numbers credible? To work this out, I will refer to another source of numbers; Professor Ferguson's epidemiological data, which I blogged about a few days ago. Professor Ferguson, at the beginning of February, calculated that 50,000 new cases were appearing ever day and that the number of infected was doubling every five days. I'll also make use of a Hong Kong study that estimated that 75,000 people were infected; this value seems to have been gathered during January. Until recently, the John Hopkins data also showed, in Hubei province where the epidemic began, that recoveries from hospital were at the same level as deaths. The Lancet data showed that in January, in one Wuhan hospital, 11% of those hospitalised died quickly, during the early stages of the epidemic, due to multiple organ failure.

I will also factor in time-lag. It has become clear that the virus can take up to a month to kill its host, after symptoms set in. If we factor in this time lag, the death rate is likely to be much higher than the Lancet figure. Is it the 50% death rate of those hospitalised, shown in the John Hopkins figures, correct? Rumours are leaking out that 50% of those hospitalised do die.

Putting all this information together, I've made a spreadsheet that roughly matches the numbers of Professor Ferguson models, and the Hong Kong study. Here is the spreadsheet:

coronavirus-timeline

To keep the graph simple, I've done several things. Firstly, I've split the timeline into fortnights. Professor Ferguson's epidemiological models indicate that the epidemic infections are doubling every five days. Therefore, in a fortnight, the number of infections has gone up approximately eightfold (more on this in a bit). I've then treated each month as two fortnights. This is clearly not very exact but it'll do for this simulation.

We can see, in the lemon-yellow area, the situation in China at the beginning of this month. It matches the tested and death rates. It's worth noting that the values for infected, symptoms and deaths in that fortnight are what happened in that fortnight. They are not accumulations. This isn't too relevant when something increases eightfold every fortnight, because the new deaths eclipse what's gone before.

With regard to testing, I've set the number of people that can be tested to start at 80 at the beginning of December. They then double every week, to simulate deliveries of more testing kit. As we can see, there comes a point where testing can't keep up with the infected. We can see that the Tencent leak values of infected and dead, according to this model, seems accurate. The daily-new-infection rate also matches Professor Ferguson's new-infections-rate.

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One very important point to note, Professor Ferguson has estimated a doubling rate of every five days. As far as I can tell, this value refers to the time when protective measures are in place (such as masks, hand-washing, self-isolation etc). This would correspond to a reproductive rate of 3 to 5… but what was the reproductive rate before these protective measures were in place? What is the disease's uninhibited reproduction rate? I am beginning to wonder if the disease actually has a base reproduction rate of far more than 5. Scientists are notoriously cautious with their estimates, to avoid appearing reckless. In order to make the disease's early emergence match the reported dates, I doubled its rate of spread during the unprotected period. This would imply that the Wuhan coronavirus has a basic, uninhibited reproduction rate of 10 or more.

If the Wuhan coronavirus did have a reproductive rate of 10 or more, when no protection measures were in place, then that would mean that the Wuhan coronavirus spreads more like measles in unprotected populations. This high number would explain the reports of 'super-spreaders' of the virus, such as the recent Brighton case and several notorious patients in Wuhan. It may be that these people are not 'super spreaders'. Instead, this is how rapidly the disease spreads on average. The idea that the Wuhan coronavirus might spread as fast as measles isn't too far-fetched. Measles is also an RNA virus. It is structurally similar to a coronavirus, apart from the protein 'corona', and it has a base reproductive rate of 12 to 18. It may be worth thinking of the Wuhan coronavirus as MERSles; it may not have as high a lethality as Middle East Respiratory Syndrome, but it has most of the symptoms of that disease and the infection rate of Measles.

If we examine the spreadsheet's data, the speed of the epidemic becomes clear. It began in Wuhan at the beginning of November and it would probably have been noticed by a hospital in mid-November. During December, the Wuhan hospitals would have been able to deal with the influx of patients but they would still have struggled to understand what they were dealing with. By mid-January, theorising would be gone. All of the Wuhan hospitals would be overloaded (I guessed that 30,000 ICU beds was the total available). They would be unable to do much more than fire-fighting, and in a state of crisis.

As shown at the top of the spreadsheet, different countries start this disease at different times. Here in the UK, we're in fortnight 2, in the unprotected time. According to the chart, next month, after dozens have died, we all start wearing masks.

I would dearly love it if the disease was diminishing, implied by the latest official Chinese numbers, but I think we should assume that they're not. The disease may not turn out to be as bad in the UK as it is in China, but I think we still have to prepare for the worst-case scenario and take rapid preventative action as soon as possible.