From the horse’s mouth. Received this morning from a Chinese source who is a top class engineering expert.
Some of the actions of the Chinese government, which seemed counter-intuitive at the time, became quite clear from this explanation.
- How the hell did they decide to close up Wuhan when the official death figure was only 30 something?
Remember that the city is a uniquely important communications hub with air, rail and river transport crossing in multiple directions (in a war they’d probably prioritize bombing the place). The time was just before the Spring Festival before the annual spring travel crush started. Closing Wuhan spoils the SF(CNY) for a huge number of people, hurts the feelings of even more and damages the economy significantly. The modelling teams were assembled much earlier than this date and this action was significantly model-driven. The models tested different actions and the actual sequence was chosen as the least bad one. Closing Wuhan on its own looked stupid to some degree, but not as the first of the sequence of actions that followed:
- What about the rest of the country then?
The rest of the country was allowed to continue through the first phase of the spring travel rush, which decanted probably 1/3 of the population from large cities onto the countryside, then the entire country was closed down preventing their return. This prevented the appearance of another Wuhan, with which the government would have no way of dealing.
- Volunteering albeit under peer pressure is a key
As it happened, they were able to assemble large teams of medics from elsewhere in the country (the so-called volunteers – if you were a party member not volunteering was not an option, and non-members esp. low ranking nurses had incentives such as conversion from contract worker to full-time permanent worker) to descend on Wuhan and its province Hubei en masse. This depletion of medical strengths elsewhere proved sustainable because another flareup never happened. The President did not formally thank the people of Wuhan on behalf of the nation for nothing. When the people of China hear western media portray this as an apology for government errors they find this play quite difficult to imagine/understand. The hard/cold decision was to contain the spread locally from the first and therefore those local people had to suffer more hardships without volunteering. The least the nation could do is to appreciate this.
- Fangcang – makeshift hospitals are effective
The establishment of the fangcang (makeshift hospitals using stadiums and exhibition centres) seemed strange, given that you were assembling ‘suspected cases’ all in one single space. The models predicted success which was borne out by reality. This has to do with how you want to deal with suspected cases and confirmed cases with light symptoms. It was determined that these people are better assembled together under professional care and control than remain at home to self-isolate with family. Fangcang-induced infections turned out to be negligible, almost zero. With beds a few metres from each other and everyone breathing the same air how was this possible? The answers are in the obligatory wearing of masks, on-hand medical and professional help and admin and enforced discipline, and almost continuous cleaning of the environment. These put together turned out to be vastly preferable, so far as the numbers are concerned, to home isolation where people do it any amateur manner they like/can.
- Testing methods with replication are crucial (real engineers can appreciate the use of time redundancy and diversity)
The testing method adopted has practically 100% accuracy in the lab, close enough to 100% to be dependable for a tested population where the infection rate is only 1%, but in the field negative results were not trust-worthy (positives are completely fine). This was also put into the models and the resulting standard changes converted a large number of suspects to confirmed in a single day (all such converted cases had negative test results, but did not pass a CT scan test). The scientists read the UK’s confident reporting of how many tested with a large proportion of negatives with fascination, and speculate that the UK may have a more reliable testing procedure. This testing situation also inspired the fangcang approach as well as the very tight lockdown measures taken across the country. You don’t get cleared just because you had a negative. You need 2-3 negatives in a row without symptoms. In other words, treat everyone as a suspect case and everyone with symptoms as a confirmed case and design your control measures based on this assumption. The CCP is able to do this, other countries maybe not.
- Modelling approaches, also diverse and competing, are a must.
The modelling gravitated towards two competing camps, by design of the government organizers. One is called the maths model and the other the medicine model. The first is led by system theorists and the second, epidemiologists. The commonly seen model of first order differential equation with an R0 factor is nowhere to be seen in either groups of models actually consulted by the decision makers – they are much more sophisticated than that. The maths model consistently returned more accurate predictions with worst case on death numbers error below 7% at all stages – this is the only hard number my friend was willing to disclose. All published models, either from within or without China which have appeared have been comparatively checked with the decision models and found to be inferior, usually by a lot.
- Future of the models?
There is very little chance of seeing these decision models published, not any time soon. My friend’s words: “We should not publish when there is an atmosphere in which such a publication might result in extra-science interpretations and uses” and such an atmosphere will linger for a long time, by the looks of it. I read the CCP propaganda as well as the stuff coming out of our government and can see this stuff buried deep for long. However the modellers continue to work on data from the wider world now and the government continues to listen to them. One difference between China and much of the rest of the world is that the scientists cannot just tell the government the science says this and that without providing evidence, as the members of the government can understand scientific evidence at an academic level. And they organize multiple teams to work against each other to form a peer-review like environment from the start.
- Protection of medics is a key factor
The most important issue, highlighted by the models and tested in real life, is the protection of the medics. Initially the disaster was when Wuhan people crowded general-purpose hospitals where the medics were not protected. When the external teams went to Wuhan+Hubei they were well prepared and formed special-purpose facilities which had a far greater success rate with next to zero infection of medics. Although this is intuitive, the actual numerical differences made in the deaths was unintuitively large.
- Ventilators is a last resort when it’s 20% survival chance left.
One of the little-publicized facts is that the starting and ending procedures of ventilator use on a patient (putting them on/off the machine) represents the standing-out worst point for medic infections. This has caused a reluctance in China of using ventilators and the threshold for their use is set quite high, leading to ventilated patients having only a 20% rate of survival – if you are not already dying you are not ventilated. So they are a bit fascinated by the current western thing about seeing ventilators as some sort of almighty saviour, esp. given the current suboptimal PPE state for medics in an environment of retired medics (presumably not young) re-joining service.
- Masks, hand washing – NOT to be neglected
On how to protect ourselves, my friend emphasizes mask wearing and hand washing – diligent mask wearing and hand washing mimics the fangcang regime to some degree. Contrary to common belief, the wearing of even three-ply surgery masks protects not only the environment from the wearer but also the wearer from the environment, and N95 masks are indeed better. He became a bit rhetorical and urged us to disregard imagined stigmatization to prioritize life, both our own and that of those who may stigmatize us.