Automated contact tracing for Covid-19 is a fools' errand
Automated contact tracing regarding infection with Covid-19 is yet another fantasy arising from PM Johnson's ill-chosen gaggle of 'scientific advisers'.
Tracing is predicated on the assumption that asymptomatic carriers of Covid-19, some of whom go onto display symptoms, can pass the virus onto others. Apparently there is 'science' making the possibility plausible e.g. suggestion of the virus being present in bodily fluids such as saliva and sweat.
Symptomatic carriers who may cough, sneeze, and wheeze, are unlikely to be out and about. In principle they are recognisable and outdoors pretty much avoidable by sensible distancing (not the ridiculous 2 metres that panders to neurotic and obsessive persons). Theoretically, asymptomatic individuals may deposit infected fluids on surfaces others come into contact with; there is already good guidance issued regarding personal hygiene, particularly hand washing, as excellent protection.
In context of outdoors, fleeting proximity to infected persons has negligible prospect of viral transmission.
Indoors, e.g. shops and public transport, chance of airborne transmission by people already displaying symptoms could be considerable especially when there is poor ventilation or, indeed, recycled air as on aircraft. Yet no practical good arises from notifying people about having been in 'contact' with infected people regardless of whether they displayed symptoms at the time. Such as actually contract infection will remain harmless to others, assuming simple hygiene is maintained, until symptoms emerge; at that point self-isolation, or enforced isolation, becomes desirable.
Automated registration of proximity 'contact' will induce further anxiety among a populace already scared by the false doom scenarios of mainstream media and the even more ignorant tittle tattle on social media; dissemination of inaccurate statistics and silly 'scientific' prognostications by government are icing on the cake of panic.
It seems likely that automated contact screening will result in an overwhelming number of false positives; false in the sense that knowledge of genuine proximity 'contact' can make negligible impact on progress of the epidemic. It may give a false sense of security too by possibly distracting people from truly sensible measures such as hand washing when exposed to objects others will have touched.
People notified of having had 'contact' will be rushing for antibody tests. This testing too is a waste of resources except for giving peace of mind to people (families too) occupationally exposed to infected persons.
The UK manifestation of the pandemic has led to headless chickens running about in Whitehall. Neither the politicians nor many from whom they seek advice appear capable of weighing and prioritising risks, of balancing benefits of measures against adverse short, medium, and long term sequelae from the measures, and of convincing any but the ill-educated mass that they have a clue about what they are doing.