This entry is a slightly adapted copy of a contribution to the interfederal working group for the contract-tracing app Coronalert for Belgium.

 Summary

  • We need urgently an effective, privacy preserving Contact Tracing APP, part of a comprehensive system of Tracing-Testing-Actions
  • There is still a lot unknown about COVID-19, such as the relative risks of person-to-person, person-air-person, person-object-person transmission, and we need more information and research on this
  • To be effective, the Contact Tracing APP must
    • record many proximity events, definitely not only 15 minutes / 1.5 meter
    • record proximity to objects, e.g. bar, restaurant, sanitary facilities in public places, train or metro wagon, etc., to replace privacy unfriendly and slow paper tracing solutions (Asynchronous and Reverse Contact Tracing)
    • have geographical awareness (not geographical tracing) in order to allow differences in nature and risk factor between areas to be accommodated
  • The APP needs to be attractive, user friendly, protect as much as possible the users’ privacy, respect smartphone resources (computing, battery), and must be working all over Europe

 Introduction

The author is deeply involved in the standardization of Contact Tracing and more generally Pandemic Monitoring in ETSI (see below)

Submitted are two contributions, this, a more general contribution, and separately, in a few days, a more technical

 Background

We have to assume that COVID-19 will be with us till at least mid-2021, more likely till the end of  2021, if everything goes well: even when we have an effective vaccine, it will take months to vaccinate the population . . . 

An effective Contact Tracing APP is an essential part of a comprehensive Tracing-Testing-Actions system that is an absolute necessity if we want to avoid further lockdowns and other seriously constraining measures.

There is still a lot unknown about COVID-19, such as the relative risks of person-to-person, person-air-person, person-object-person transmission, and we need more information and research on this.

 Basic functions of the Contact Tracing APP

To be effective, the Contact Tracing APP must record many proximity events in a way with maximum protection for users’ privacy. On the Belgian Contact Tracing web site, the following can be found:

Source: https://www.info-coronavirus.be/en/contact-tracing/#contact

I may have come into contact with someone who is a carrier of Covid-19

 Have you come into contact with anyone who might be ill right now? Were you in contact with this person for some time (more than 15 minutes) and up close (within a distance of 1.5 meters)? (For example: a housemate, a colleague sitting next to you in the office, a friend from school). This is known as higher-risk of being infected. What are you requested to do in this case?

. . . .

Have you come into contact with people in the supermarket or with a colleague who is not sitting next to you at work? This is known as lower-risk contact. What are you requested to do in this case?

 If the Contact Tracing APP would only record the higher-risk cases, then the APP is not of great value: apart from co-travellers in trains, metro, planes etc. it would only record . . . . housemates, close friends, close colleagues . . . but these are already in the Smartphone, in the telephone directory!

Instead, a Contact Tracing APP must record many proximity events, i.e. encounters of far less than 15 minutes, the lower-risk contact cases . . .

The Contact Tracing APP, now technically called Synchronous Contact Tracing, has these limitations:

  • The Contact Tracing is triggered only when a person has COVID-19 symptoms, and is tested positive: this introduces a delay of days, possible 5-8 days after an encounter, and this is considered too long to effectively avoid infection spreading
  • Asymptomatic persons spreading COVID-19 will only be identified if tested and after having potentially transferred COVID-19

 Additional functions of the Contact Tracing APP

To avoid recourse to privacy unfriendly and slow paper tracing solutions, proximity to objects, e.g. bar, restaurant, sanitary facilities in public places, train or metro wagon, should be detected by applying an extension to Contact Tracing, called Asynchronous Contact Tracing.

Furthermore, the spread and completeness of COVID-19 infections could be detected by applying tests on cleaning tools and water, and on waste water: this technique, Reverse Contact Tracing, can reveal the presence of COVID-19 positive persons, including asymptomatic, with much shorter delay, and in combination with Asynchronous Contact Tracing would warn people and initiate a testing process in hours rather than days or weeks.

 

Additional functions also to please and support the user of the Contact Tracing APP

The APP needs to be

  • attractive, user friendly
  • protect as much as possible the users’ privacy
  • respect smartphone resources (computing, battery)
  • working all over Europe

The latter maybe be not only in the hands of the Belgian developers, but it does require interoperability with other APPs at the Bluetooth and recording of proximity events level, and at the level of  information interchanged with national servers and international ‘federation’ servers.

However, the APP could do more, for science and for the users:

  • give an alarm when a person comes within a 1.5-meter perimeter
  • record as many proximity encounters, also short, and at longer distances, and provide statistics on the basis of these additional recordings:
    • indicate to the user, statistics per day or per week with the number of proximity events as a function of distance and time (scatter diagram), to judge the level of COVID-19 risk taken
    • to feed research with currently missing information

The author works on the European standardization of Contact Tracing and Pandemic Monitoring in ETSI and is a member of the ETSI groups E4P, eHEALTH and Smart M2M

ETSI                    https://www.etsi.org/

E4P                     https://www.etsi.org/committee/e4p

eHEALTH            https://www.etsi.org/technologies/ehealth

SmartM2M          https://www.etsi.org/committee/smartm2m

eG4U                  https://www.eg4u.org/