Tuesday 7 July 2020

Outbreak stages classification when it is out of control: July updates

This is an update on my model based on test count vs positive rate. For the introduction please refer to these articles:

1) Classification of outbreak stages by variation of test count and positive rate
2) Typical stage shifts: May updates


We have seen the potential of this model predicting the case trend in the next few days, but it does not give strong indication on whether we are shifting to the next stage. Even if we are to make predictions based on the model, there is one important assumption that we made.

We assume that the government would thoroughly eliminate the local infection chain to the point that only isolated cases would occur after a certain time.

This is certainly false when from what we have seen in the last two months. These countries are divided into two categories: either they lack the ability to eliminate the virus (passive herd immunity), or they try to strike a balance between public health and economy, which miserably failed. This will be the main theme of my July update.

Just like the May update, we present the trend since late March or whenever data is available, but data after May 10 will be shown in bold.


Countries that cannot control the virus at all

When the virus was spreading in South-East Asia and Africa, we feared that the pandemic could be out of control because of a less hygienic environment and less efficient/reliable government etc. This turned out not the case -- Africa is too hot for the virus, and SE Asia actually did a good job controlling the damage. Thailand and Vietnam did particularly good, for example.

But when it arrived South America such worry finally came true, as the virus easily spreads among the passionate (in other words, unhygienic) Latinos. The whole South America is quickly approaching towards herd immunity, not because they wanted to, but they have no other choices at all. The hospital was of course overloaded, and the government lacked the ability to response. The living habit of South Americans would only accelerate the infection. Rumors were in Brazil where gangs asked residents to stay at home and isolate themselves -- although unlawful this could really the be the right thing to do against the virus.

Confirmed cases for Columbia and Costa Rica exploded around late May when the shock wave finally arrived South America. Despite the slow increase in testing scale, we see no signs of things under control, at all. Columbia has been testing left and right, but they still need more -- at least 5 times of the current scale -- if you compare with other big European countries like France.

South Africa is the singularity in Africa because its climate is quite different from the rest of Africa, which is bad because they are in winter now. But the bigger problem was that the government wanted to restart the economy so they lifted lockdown too soon. Daily confirmed cases doubles every 1 or 2 days since then, and the tragedy follows from slow reaction of the government. That is a pity -- we thought they did enough to shoo off the virus, but one mistake and it was all over.


Countries that cannot eliminate the virus

When everything is under control, the next step is to eliminate the virus locally so that the economy can reboot without creating more infection. However part of the population is always kind of disobedient. They get themselves infected and eventually get others infected as well. It has been a dilemma in western countries: rebooting the economy earlier implies that you will never get the virus eliminated, and it builds a constant pressure on the health care system as well as everything else. Most countries chose economy anyway, and we are observing more of these "long tail" infections.

The fact that Japan successfully suppressed the virus on the edge of a widespread infection shows their high standard of public health maintained. This is however, not necessarily true in every single corner of the country. Most recently reported cases in Japan are actually happening in the food and service sectors -- in particular pubs, (erotic) salons, maid cafe and so on.

It would really be a hard decision to shut these shops again. The industry is extremely fragile and already took a heavy blow in the past 3 months. On the other hand, infections are likely to happen in these places again as long as the virus is not exterminated completely, that they could be forced to shut indefinitely.

Russia as well as Singapore and some other middle-east countries are of another story. The infection is confined to the circle of foreign labours, whose are socially isolated from the general public and have a below-average living standard. Given their status in the host countries, it was deemed not worthy to eliminate the virus within those communities, so an alternative is to isolate all these workers as a whole, and hope that herd immunity would develop eventually there.

The United States case is so complicated... each states has its own problems. First of all the protests. Regardless of their motives, this is bad for disease control. Secondly lockdown was lifted a bit too early in some states like Florida and Arizona. The southern states also received an influx of patients from Central and South America, where things are apparently uncontrollable. Imposing the lockdown again is the right choice, but protests and the effects from neighboring countries would drag back the effectiveness of the lockdown.


For the rest of the world, UK is apparently reopening its border for most travelers knowing that their own immunity is good the point where taking ill travelers is of no big deal anymore. We are also observing relaxation of border control among countries that eliminated the virus like Taiwan and New Zealand. It would be fun to observe half of the world recovering, and the other half still fighting hard against the virus.


[1] Total confirmed cases vs total tests conducted, retrieved 5 July 2020.

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