Contact-Tracing Approaches to Fight Covid-19 Pandemic: Limits and Ethical Challenges Sara Hsaini, Hayat Bihri, Salma Azzouzi, My El Hassan Charaf ISO-Lab: Laboratory of Informatics, Systems and Optimization Faculty of Science, Ibn Tofail University Kenitra, Morocco hsaini.sara@gmail.com, hbihri@gmail.com, salma.azzouzi@gmail.com, charaf@gmail.com Abstract— COVID-19 pandemic is the largest worldwide sanitary and economical crisis of modern time. According to the World Health Organization (WHO), the new corona virus is spreading rapidly from person to person through contact transmission. To fight the COVID-19 outbreak, a number of strategies have been implemented at the population level, such as social distancing, testing and contact tracing. In this work, we focus on contact tracing, which is considered an effective public health measure to control the spread of this disease by identifying and tracking potential persons who may have been in contact with a COVID-19 infected person. To this end, we review various approaches and existing contact tracing applications used by various governments around the world to monitor and control the spread of this disease. Then, we discuss the limits and ethical issues of such digital contact tracing solutions. Keywords— COVID-19, contact tracing, pandemic, positioning, surveillance. I. INTRODUCTION Nowadays, the widespread and high transmission rates of COVID-19 are the main risk factors that led the World Health Organization (WHO) to declare this disease as a public health emergency of international concern. For centuries, infectious diseases have been considered a major threat for humanity and can destroy entire populations. Therefore, understanding the disease remains the only way to control and limit its spread. In this context, modeling has been widely used to understand the spread of diseases and to determine the best strategies required to reduce their impacts [1]. Within the context of the current health crisis, several modeling studies have been carried out to understand the nature and characteristics of COVID-19 disease. These investigations show that the process of identifying susceptible individuals will help to control the pandemic spread, especially now as many countries around the world are moving towards the lifting of containment. In fact, the purpose of contact tracing is to control the spread of a contagious disease [3] and it was commonly used as an ancient procedure and an indispensable step in the strategy to fight previous epidemics such as Ebola and Tuberculosis [4]. To this end, many governments around the world rely on contact tracing methods to monitor and limit the spread of the COVID-19 pandemic [2]. Furthermore, the WHO organization has recommended it as one of important population-wide strategies to tackle against COVID-19. Obviously, Contact tracing can be performed manually, by human tracers, who interview the infected persons about all their recent contacts and then follow them © IEEE 2021. This article is free to access and download, along with rights for full text and data mining, re-use and analysis. [5]. However, this traditional method is not very effective in identifying all susceptible contacts as it is based on the memory of the infected persons, who cannot remember all individuals who have been in close contact with them during the period where they were potentially infectious (up to 14 days). Moreover, it is also impossible to trace potential contacts that have in close contact with the infected person in public transport or public spaces. Therefore, the study [6] shows that the use of technological applications, carefully designed, can help make the contact tracing process more efficient. In this context, several countries around the world use -or debate- different approaches of contact tracing on mobile apps to control the COVID-19 outbreak dissemination. In fact, the key to ongoing containment of the pandemic in Singapore and several provinces in China is the use of contact tracing app that help to limit the number of their initial outbreaks [7]–[9] by identifying many new cases, often before symptom-onset which decrease significantly the likelihood of sustained transmission [10], [11]. Moreover, such solutions were also effective to reduce the spread of the disease in China and South Korea during the widespread transmission period [8], [12], [13] even if the diversity of technical solutions proposed for contact tracing has solicited a debate on their practical effectiveness and ethical issues. In this survey, we present a review of all contact tracing approaches used by different countries to tackle against the COVID-19 pandemic. Then, we discuss the limits and issues encountered by governments while deploying such solutions on mobile applications. The paper is organized as follows: Section 2 gives basic concepts related to the contact tracing. In Section 3, we describe different approaches of contact tracing and their limitations. Section 4 presents an overview of some existing mobile applications serving to trace the disease dissemination. In sections 5 and 6, we introduce some ethical challenges. Then, we discuss issues that can limit the effectiveness and efficiency of these applications. Finally, the section 7 gives conclusions and identifies future works. II. CONTACT TRACING A. Principe Contact tracing allows identifying each person in close contact with someone infected with a virus, such as COVID- 19. The aim is to control the pandemic spread by breaking the chains of transmission of infection [14]. In contact tracing process, a contact is a person who has experienced any of the following cases during the two days 2020 IEEE 2nd International Conference on Electronics, Control, Optimization and Computer Science (ICECOCS) | 978-1-7281-6921-7/20/$31.00 ©2020 IEEE | DOI: 10.1109/ICECOCS50124.2020.9314512