The tracking that the Immuni app should perform will be impossible. The analysis of Franco Battaglia, physicist and teacher at the University of Modena
Finally a politician who knows how to discern things: Fedriga, president of the Giulio-Friuliana region, has withdrawn his availability for experimenting with the smartphone application for tracking contacts. And he did very well. In the event of an epidemic or, as in this case, a pandemic, it becomes crucial to operate in such a way as to bring to values below 1 the now known to all reproducibility factor, R0. This factor – which indicates how many people, on average, infects each person already infected.
As long as R0> 1, the infected grow inexorably, while if R0 <1, they end inexorably with exhaustion. For example, one of the most infectious viruses is that of measles, for which R0 = 15. The virus that concerns us at the moment would have an R0 value between 2 and 3, the same value as the typical flu viruses. To reduce the R0 value there are two techniques: lockdown (LD) and contact tracking (TC).
To paraphrase Mao Tse Tung, the spirit of the LD is to hit 100 to educate 1. Apart from my personal evaluation, for the good result from both techniques the crucial factor is the time factor. Our country – and, to tell the truth, not only ours, but most of the western countries (among them I would exclude Germany) – has been guilty inefficient on the LD, as our 33 thousand deaths testify. For one thing, just to understand the climate, let's not forget that on the same day (February 8) when, for example, South Korea closed its borders to the Chinese, the mayor of Florence launched the hashtag #ioabbracciouncinese. Our government, for guilty incompetence, started the LD with at least 3 weeks late, when the dead were already a few hundred.
TC, the technique successfully used in South Korea, requires the same speed of action (the Asian country had zero deaths when it took the first steps). In the absence of capillary diagnostics on the asymptomatic population, it is necessary to resign oneself to the information on the symptomatic. To understand the timing well, it must be considered that if the incubation time (i.e. the time between infection and disease symptoms) can go up to the famous 14 days, it is typically about 5 days, but has already been around 2 days before symptoms occur that you have the maximum ability to infect.
It is therefore crucial to trace – and quarantine – the contacts that each infected had from the 2 days preceding the day the infected had experienced symptoms until the day when he was recognized as positive (the day beyond which he is isolated). And you have to do it quickly, because a contact of the infected that ended up developing symptoms (typically, as mentioned, after 5 days) could in turn infect those with whom he had contact in the 2 days preceding his symptoms. And so on, with an unpleasant chain reaction. The speed of action is therefore crucial.
I read that the UK, after abandoning the idea, to say the least extravagant, of herd immunity, is starting a CT program, with a small army of 25 thousand "investigators" enrolled for the purpose. Very well! They will have a painstaking job to do: call every single new infected person, make them list the contacts that they remember having, then call each of them, announce the "good" news, and convince him to stay in quarantine for 14 days. , providing all the appropriate support.
It is not difficult to understand how the "manual" process just outlined can receive considerable help from current technology. For example, the existence of a single electronic archive where all the infected were inserted, would allow "investigators" to draw directly from the archive to relate to the sick to obtain from them the names of their contacts, to be inserted in turn in the archive. This is a first aid which would greatly facilitate the necessary continuous relationship between investigator and contact.
Another problem that the TC operator has to face is the difficulty in reconstructing the positive contacts, either because he does not remember them or simply because he is reticent. Some governments – certainly the case of the Chinese one and probably also of the South Korean one – have a centralized archive, all their citizens are registered, and at any moment the government is able to trace them and know their health record. And, via satellite, also know the location and movements of their mobile phones. In this way, health professionals can identify in real time all the contacts of a positive and quickly connect with them to plan their quarantine.
Meanwhile, this system poses a legitimate problem of confidentiality, which cannot be quickly dismissed with an alleged superiority of the right to health: a moment of reflection should make it clear that things are a bit more complicated than some would like them. Then, the GPS system is not so precise: the fact that this tells you that you have been in the same market with a positive does not mean that you have had potentially infectious contact with it. Only authoritarian systems like the Chinese one or super-organized ones like the Korean one can handle such control.
Alternatively, using Bluetooth technology, smartphones equipped with the appropriate app are in some way in communication with each other: if you who are positive enter this information in your smartphone, all those who, equipped with the same app, have been close to you receive the information that you have potentially been in contact with you. Circumstance that could create unjustified panic. In case, then, if you develop fever or some other symptom, you should enter the information in your smartphone, so that all those who had potentially been in contact with you are informed.
At this point, meanwhile, panic is assured. Confidentiality is also ensured, because only contact knows it is; but it is also insured against the health system, which knows nothing about what is happening. The mechanism leaves the discretion of the contact whether to quarantine alone or not. In short, we would have a monitoring system, unrealistic like all monitoring without consequent certain actions. In the end, we can confidently conclude that that of President Fedriga was a prudent choice. Bravo, Fedriga!
(Excerpt from an article published on the website of Nicola Can, here the full version )
This is a machine translation from Italian language of a post published on Start Magazine at the URL https://www.startmag.it/innovazione/perche-lapp-immuni-non-funzionera/?utm_source=rss&utm_medium=rss&utm_campaign=perche-lapp-immuni-non-funzionera on Sun, 07 Jun 2020 05:50:40 +0000.